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Full text of "Earthwork In Railway Engineering"

t 1C. BOOK No. 



VJI 



PROPERTY OF THK 

CARNEGIE INSTITUTE OF TECHNOLOGY 
LIBRARY 



ACO. 



THE GLASGOW TEXT BOOKS OF CIVIL 

ENGINEERING. EDITED BY G. MONCUR, B.Sc. 

M.I.C.E. Professor of Civil Engineering in the Royal 

Technical College, Glasgow. 



EARTHWORK IN RAILWAY 
ENGINEERING 



THE GLASGOW TEXT BOOKS. 
EDITED BY G. MONCUR. 



EARTHWORK IN 
RAILWAY ENGINEERING 



BY 

JOHN W. F. GARDNER, M.lNsx.CE. 




NEW YORK 

D. VAN NOSTRAND COMPANY 

EIGHT WARREN STREET 

1930 



PRINTED IN GREAT BRITAIN 



PREFACE 

THE purpose of this book is to describe in a practical manner the 
underlying principles which control earthwork undertakings, so 
far as they relate to general railway work* 

It has not been possible in the limited space available to deal 
fully with certain matters and preference has been given to the 
points more directly affected by the actual constructional work. 

In view of the uncertainty of the character of the material to 
be met with, no hard and fast scheme of operations can be adhered 
to, and the methods of procedure hereinafter referred to should be 
taken more as a guide to what course or design to follow. 

The author would emphasize the importance of thorough con- 
sideration being given to drainage works, and matters relating 
thereto have been given special attention. 

The particulars in regard to constructional work are for the 
most part the result of experience gained by the author when 
acting as Resident Engineer under Mr. Donald A. Mathe&on, 
formerly Engineer-m-Chief, now General Manager of the Cale- 
donian Railway, and he takes the opportunity of placing on record 
Ms appreciation of the valuable assistance received from him. 

J. W. P. GL 



CONTENTS 

CHAPTER PAGE 

I. PRELIMINARY INVESTIGATIONS AND ESTIMATES OF COST 1 

II. INVESTIGATION AS TO STRATA 9 

III. CULVERTS AND DRAINAGE 18 

IV. EXECUTION OF EARTHWORK 36 

V. PLANT USBD IN EXECUTING EARTHWORK ... 77 
VI. SLIPS IN EARTHWORK AND THE MEANS TAKEN TO 

PREVENT THEM 99 

VII. MAINTENANCE OF EARTHWORK 127 

VIII. CONDITIONS AFFECTING THE COST OF EARTHWORK * 134 

IX. SpBcmoATiON ..... 142 

INDEX . .*.*... 149 



LIST OF ILLUSTRATIONS 

FIG. PAGE 

I Cutting for single line ......... 2 

2. Cutting for double line ........ 3 

3. Difference between cutting for single and double lines ... 3 
4. Chisel boring . . . . . . . . . .12 

5. ** Crown " of diamond drill . . . . , . . .15 

6. Water openings in embankments ....... 21 

7. Fire-clay pipe drains under railway . . . .22 

8. Timber box drain under railway ....... 22 

9. Built stone drains under railway ....... 23 

10. Arch culverts under railway ........ 23 

11. Culverts with steel beams and concrete covering . . . .24 

12. Pipe conduit under railway embankment on side-lying ground . . 25 
13. Stepped arch culvert on side -lying ground . . . . .26 

14* Design of enda of culverts ........ 28 

15. Two water-courses conveyed in one culvert under railway . . 29 

10. Water channel diverted along contour of sloping ground - . .31 
17. Road and stream diversion carried under railway at one place . . 32 
18. Syphon pipe under railway ........ 33 

19. Ripe carried over railway on trestle ...... 34 

20. Pipe carried over railway on road bridge . . . . . .35 

2L Water-eourse carried over railway in open conduit . , . .35 
22. Stream and road carried over railway on one bridge . . . .85 

23. Contract general plan ......... 38 

24. Contract longitudinal section ....... 38 

25, Contract -cross Bectioos ........ 41 

26. ffbdttg slope stakes 42 

27. Area of cross section ......... 43 

28* Working longitudinal section 45 

29. Soft outtting overlyiog rook ........ 50 

30* Exeavatog cutting 10 to %0 ft* deep ,52 

3L< WMth required by steam digger ..... 5$ 
8& Leaving wings on gullet ,...... 58 

3$* Catting into slope ......... 54 

34 Ancwgwueat In cutting three lines of railway .... 55 

S5 Arrangement im cutting tw lines of railway ... * . 56 

&& Arrgneat at embankment end 57 

of expeditlag emptying wagoiw .*...& 
xi 



xii LIST OF ILLUSTRATIONS 

FIG. 

38. Excavating rock .......... 62 

39. Example of railway cutting (1) . . . . . .64 

40. Example of railway cutting (2) . . . . . .66 

41. Example of railway cutting (3) ....... 66 

4S. Cross section of railway through bog land ..... 68 

43. Section of railway approaching bog ...... 69 

44. Widening of railway single to double line . . , . .70 
45. Widening of railway two lines to four lines ..... 70 

46. Excavating rock by "plug and feather '" ...... 78 

47. Ruston steam crane navvy . . . . . . . .81 

48. Ruston steam crane navvy ........ 83 

49. Wilson steam crane navvy ........ 84 

50. Wilson steam crane navvy (with bent jib) . . . . .85 

51. Ruston steam shovel ......... 86 

52. Lubecker land dredger ......... 88 

53, Ingersoll-Rand rock drill 00 

54. Hand hammer drill ......... 02 

55. Iron tip wagon .......... 94 

56. End and side tip wagons ........ 05 

57. Drain for intercepting field drains and surface water . . .101 

58. Slope drains in cutting . , . . . . . .105 

59. Large slope drains with toe wall at foot of slope .... 107 

60. Dryston dwarf wall at foot of slope . . . . , .108 

61. Flat slope in loose rock cutting ....... 16f 

62. Face wall in rock cutting . . . . . , .lid 

63. Retaining wall in soft rook cutting . . . , . ,111 

64. Slip of small dimensions in catting . . . . .112 

65. Slip of large dioaeoisions in cutting . . . . . .112 

66. Slip in cutting requiring special treatment . * . . .114 
67. Section in cutting with large volume of subsoil water . , . 1 15 
68. Slip in embankment on side-lying ground . . * .121 
69. Intercepting subsoil wat^r under emlbajakment , . . ,123 

70. Cross sections of British permanent way ...... IBS 

71. Part cross section of Pennsylvania railroad, America. . . . 1S2 

72. Form of cost statement for earthwork undertakings . . , .1)0 
73. Detailed statement of cost and output of railway cutting , . .186 
74. 3>igra.m of cost and output of railway cutting * 1S7 



EARTHWORK IN RAILWAY 
ENGINEERING 



CHAPTER I 

PBELIMINARY INVESTIGATIONS AND ESTIMATES 

OF COST 

THE location of a railway is for the most part governed by geo- 
graphical considerations, but the promoters of the undertaking 
will look more to the proposal from a financial point of view, and 
in their deliberations they will be guided by the Engineer as to the 
practicability and probable cost of the work. 

Various proposals will no doubt have to be examined before the 
scheme which is to be carried out is decided upon, and, in view of 
the importance attached to the Engineer's report, it is essential 
that he be thoroughly informed in all matters which may influence 
the decision of his clients. 

While none of the proposals which are considered may be 
altogether impracticable, yet the carrymg out of the project may 
only be done at a loss, It is impossible to foresee aE the difficulties 
that may be met with during the progress of a particular work, 
but these may be very considerably reduced by more particular 
examination of the details of the project by the Engineer when the 
scheme is being developed. 

It has been truly said that ** It is much easier to make an expen- 
sive railway than a cheap one under the same circumstances, and 
the object of every Engineer ought to be aa far as possible to 
adapt the work he has to design to the results to be obtained/* In 
a through main lino of railway, heavy works mck m tunndli 
tege bridges will in all probability require to be executed in 
that the curvet may be as easy as possibly moA strop 



2 EARTHWORK IN RAILWAY ENGINEERING* 

avoided, and large expenditure may be justifiable, whereas, in the 
case of branch or secondary lines, the Engineer may have to be 
content with steeper gradients and sharper curves if he is to keep 
the cost within moderate limits. Consideration of each different 
project must, however, be governed by the particular circum- 
stances of the case* What may be an economically constructed 
railway in one place, may be a wasteful expenditure in another. 

Questions relating to location which are affected by traffic 
working do not fall to be considered here, and the preliminary 
investigations which are referred to deal with matters affecting the 
actual execution of the work. 

The estimated cost of the works which the Engineer prepares 
should represent to a nearness what the ultimate expenditure wiU be. 

The first cost of a railway may be reduced by making a detour, 
but, on the other hand, the annual outlay in maintenance or work- 
ing of the railway may be increased in consequence of the additional 
length to such an extent that no real saving will be effected. 
The expediency of making a diversion may arise from a desire to 
avoid interference with valuable property, or to save the expense 
of the construction of a large bridge, tunnel, river diversion, or 
other important work, or it may be that the materials likely to 
be met with in the cuttings or under the site of the embankments 
are of a treacherous character, or the cost of the earthwork may be 
excessive. These, and other circumstances, may have so added to 
the initial estimated cost of the shorter route as to make a diversion 
imperative, and it should be further noted that the more heavy 
the description of the work the greater generally is the after cost 
of ;maintenance. 

When considering whether the works should be constructed for 




Fi<*. 1. Cutting for single line. 

a single or double line of railway or of a greater width, it should be 
kept ia view that the cost of the earthwork is not proportionate 
to the number of Hues of railway. 



PRELIMINARY INVESTIGATIONS AND ESTIMATES 3 

Referring to Figs. 1 and 2 the areas of sections for a cutting 
20 ft. deep and with the usual side slopes for soft material are for 
single and double lines 980 square feet and 1200 square feet respec- 
tively, the increase of the double over the single line section being 



Area 1200 S<f. Ft. 




FIG. 2. Cutting for double line. 

about 22^ per cent. This increase is represented in Fig. 3 by a 
vertical strip 11 ft. wide, and roughly indicates the increased cost of 
the earthwork with cuttings and embankments of an average depth 
of 20 ft. for a double line of railway over a single line of rail- 
way. The excavations for the greater width would cost a little 





L 3. Difference between cutting for single and double lines. 



less per unit of volume on account of the service roads and 
other temporary works and plant required during construction 
not being proportionately increased, and also on account of there 
being greater facilities for carrying on the operations, but for all 
practical purposes the same unit rate may be used in preparing the 
preliminary estimatf s of cost, 

If there is a likelihood of the railway being widened at some 
future time it may be advantageous to acquire land for the wider 
liae to begin with, although the constraetion of the wider liae 
may be deferred to a luture date. 

IE the constracta<m of the partial scheme the quantity of 
nmterials in the cuttings may be in expom of ifae quantity 
required to form the mbankmente, and the surplus excavated 
should be deposited in the embaiikm^iite for the ultimate 



4 EARTHWORK IN RAILWAY ENGINEERING 

widening, or for station yards which may be contemplated in the 
future, if these are conveniently situated to the cuttings. 

In fixing the width of formation regard must be had to the future 
maintenance of the railway. The additional cost of constructing 
cuttings and embankments a foot or two wider so as to obtain 
better drainage in cuttings and greater solidity in embankments is 
small compared with the extra periodical expenditure in main- 
tenance incurred by the construction width being restricted. By 
increasing the width of a double line cutting 20 ft. deep and in 
ordinary soft material from 28 ft. to 30 ft., the quantity of ex- 
cavations is increased by only 3-| per cent. The advantage of 
having sufficient width of formation is referred to in Chapter VII, 
page 130. 

Consideration must also be given to the curves and gradients 
of a railway. With a diverted or longer route, better gradients may 
be obtained than with the direct route, but with the latter there 
will probably be a better alignment. These matters will reqwre 
to be considered from a traffic working point of view before the 
route is finally decided upon* 

In settled cotintries there is not the same opportunity for 
railways being made on constructionally economic lines on account 
of the proximity of valuable land and property, but in undeveloped 
countries where land is either given free or is comparatively cheap 
considerable attention is now being paid to the question of 
economics in construction which will undoubtedly effect large 
savings in carrying out the undertaking and also give a better 
return for the capital expended* 

In laying out the line of a railway or road, endeavour should be 
made to reduce the quantity of earthwork to a minimum, and the 
fonnation level should, consistently with other considerations, be 
fixed so that the quantity of suitable material excavated froujL 
the cuttings will just be sufficient to form the embankment. It 
must be kept in view that all unsuitable materials should be ram 
to spoil and allowance also requires to be made for the quantity of 
excavations which may be used for constractional purposes* It is 
a considerable advantage to have the " lead " (haul) to embank- 
ment on a down grade and as short as possible. 

The cost of the work, as will hereafter be shown, is largely 
dependent upon the relative positions of eii&ragp Mtck ^oalwakBpLWits. 



PRELIMINARY INVESTIGATIONS AND ESTIMATES 5 

Under certain conditions it may be advantageous to run some 
of the materials which are quite suitable for embanking purposes 
to spoil embankment rather than run them for a considerable 
distance on an up grade. To make up the deficit of embanking 
materials thus caused, side cuttings or borrow pits may be 
necessary, and while this would incur the additional cost of 
excavation it may be a cheaper method to adopt. Where 
furnace ashes can be obtained in large quantities and at little cost 
no better material could be obtained for making an embankment 
and the work of depositing them can be carried on very speedily. 
An embankment constructed of ashes will also entail a minimum of 
expense in subsequent maintenance. 

The site of a spoil bank should be convenient to the excava- 
tions and have an easy access with a minimum of expenditure for 
wayleave, use of ground, subsequent restoration and for depositing 
the material. A mistake may be made by using moss land or 
other similar site where the ground can be cheaply obtained, as there 
may be considerable expense incurred in making up and constantly 
repairing service roads while the material is being deposited. 

The simplest construction for a railway might appear to be where 
the work is executed on side-lying ground, partly in cutting and 
partly in embankment, and with just sufficient material in the 
cutting to form the embankment. If the material excavated is of 
an earthy description and can be removed without any slipping on 
the upper side taking place the conditions would be favourable, 
but if, on the other hand, there is a tendency for the ground to 
slip by reason of the support which formerly existed having been 
removed, the work may be very costly to execute* This matter 
is fully considered in subsequent reference to slips. 

In skirting hillsides it is frequently found that the natural slope 
of the soft material overlying rock is inclined at the angle of repose 
of the material, and it is thus desirable under these conditions to 
have as little cuttiia.g as possible* The material necessary for 
eixibaBJkiag purposes could then be obtained either from adjoining 
cuttings where the surface was at such an ungle as to prevent Blips 
or it could be got from borrow pits. In the latter contingency the 
ertrs cost of side cutting wouM be incurred, but this cotoe may 
ultimately prove to be the more economical focm of oonstractioa. 
A iiMJhl pmctice in countries where there are mwm ano wto^ms is 



6 EAETHWOEK IN EAILWAY ENGINEERING 

to dispense with cuttings almost entirely and thus avoid obstruction 
to traffic by snow blocks, the banks being made up by material 
taken from borrow pits. Apart from the question of snow blocks 
a railway on embankment is less costly to maintain. 

The side ditches in a cutting require to be kept clear of materials 
washed off the slopes or which may have collected, and which if 
not removed will tend to keep the formation of the railway in a 
wet sodden condition, to the detriment of the permanent way. 

In countries where timber is plentiful, ravines necessitating what 
would be long high embankments may be temporarily spanned by 
trestle-work so as to speedily complete the line of communication, 
and at a later date the embanking materials would be deposited. 

Again, by following closely the line of a water-course the presence 
of moss, clay, or other soft material may be the cause of serious 
trouble, either in a cutting or in an embankment, and therefore 
the possibility of more material being excavated or more material 
being required for embankment than originally anticipated should 
not be overlooked when locating the proposed works. 

In rough hilly country, where there may be a large exposed 
surface of loose friable rock and boulders, the streams will, after 
frost and during torrential rain, carry in their course a considerable 
quantity of stones down the hillside which will be deposited on the 
plain below. 

If the railway were constructed on the flat land at the foot of 
the hill, any water openings would then be liable to be choked up, 
and the railway should, therefore, be constructed on the hillside 
where the velocity of the water is still great enough to carry the 
stones through the water openings. 

Further, the water-courses which are confined to narrow channels 
on the hiUside will open out and spread over a wide area on the flat 
ground, which in flood-time will thus be under water, and if the 
railway were constructed on the low ground considerable damage 
might result before the water passed through the flood openings 
in the railway embankment. Reference to allowing flood water to 
pass entirely over low railway embaoikmente is made in Chapter III, 



The cost of the tindertaMng will largely depend on the character 
of the materials met with during construction, and it is 
that ihe Mbst information b& aac^rfeaini in rewd to ft* 



PRELIMINARY INVESTIGATIONS AND ESTIMATES 7 

For the purpose of the preliminary estimates, this information will 
have to be obtained from general observations of the surrounding 
country., and from geological maps of the district, if these are 
procurable. In the absence of actual bores or trial pits on the site 
of the works, the depth of soft material overlying rock and the 
characteristics of that material would be more or less indefinite, 
but after such arrangements have been made as will allow of a 
complete series of bores being taken or trial pits sunk, the fullest 
particulars should be obtained. 

The cost of obtaining information in regard to the strata is so 
small in comparison with the results obtained that in work of any 
magnitude the question of expense should be a secondary con- 
sideration. 

The extent of land necessary for both cuttings and embankments 
is dependent upon the character of the materials in the cuttings 
and under the sites of the embankments. If the works are being 
constructed through or in the vicinity of valuable property retaining 
walls may be required to support the sides of a cutting, or reduce 
the area of land covered by embankment, and the cost of these 
contingent works has also to be estimated. 

The Engineer must keep in view the possibility of the materials 
requiring flatter slopes than would at first sight appear necessary 
and the probability of retaining walls having to be provided to 
retain the slopes within the land acquired or the necessity of more 
land being required than was originally contemplated. If more 
land has to be bought after the works are commenced a larger rate 
will most likely have to be paid for it. If these matters are lightly 
passed over the original estimates will in all likelihood be largely 
exceeded when the works are completed. 

In the initial stages of an undertaking it is generally necessary 
that secrecy be observed, and, in view of this fact, and also on 
account of the short time usually allotted for the preparation of 
preliminary enquiries, the estimates of cost may be of a somewhat 
incomplete description. An exact section of the ground may not 
be available, but efficient information can generally be obtained 
from " spot " levels of the more prominent points, and by making 
fuH t*se of the levels and contour lines which, are laid down on 
Survey maps. For the purpose of calculating the quan- 
of oaxtteorfj: a&d fox a^ertidning -the bo wdariea of ifoe Iaa4 



8 EARTHWORK IN RAILWAY ENGINEERING 

required typical cross sections should be prepared, and in open 
country these might be at intervals of from three to five chains 
apart. 

In view of the approximate description of the preliminary esti- 
mates an ample allowance say 10 to 15 per cent of the whole 
should be added to the cost for possible contingencies, so that the 
total sum will prove adequate for the execution of the proposed 
work. It is better that this estimate should be over rather than 
under the actual cost of the undertaking, so that the promoters of 
the scheme will not be misled, but unfortunately it too frequently 
occurs that preliminary estimates are considerably understated. 

Where estimates of costs are subjected to the criticism 
of rival Engineers or Parliamentary Committees, and when the 
various details on which the figures are based are subjected to the 
closest scrutiny, it is most desirable that the assumptions both as 
regards quantities and rates should be well founded* 

After Parliamentary sanction has been obtained or agreements 
have been made with the proprietors of the land on which the pro- 
posed works are situated, complete longitudinal and cross sectkteef 
of the ground should be taken and a thorough investigation made 
of the strata so that the ex^ct line of the railway may be determined 
and a Mly revised estimate of cost prepared. The quantities of 
the materials of this new estimate will form the basis for the subse- 
quent Contract Schedule and these should be as full and complete 
as possible. Special consideration should be given to the unit 
prices for each item of work. The probability of an increase of the 
cost of labour or materials during the period of construction and 
the possibility of interruption by reason of wet weather and conse- 
quent loss should also be kept in view. 

The magnitude of the work will also influence the unit cost. In 
works of small dimensions on which it would be unprofitable to 
place large and expensive plant the cost would be proportionately 
more than where mechanical excavators, etc., ew be advan- 
tageously used* The more complete the iaxforaatioB is that affeote 
tile quantities or prices the nearer will be the amount of the 
Tender to the actual coat of the work, in which case the 
wilt be mow satisfactory to both contacting parties. 



CHAPTER II 

INVESTIGATION AS TO STRATA 

IN earthwork undertakings tlie principal matter that affects the 
quantities and prices in the Detailed Estimate on which the Con- 
tract Tender is based, is the character of the strata under the site 
of the works. 

It is thus of the first importance that definite and reliable informa- 
tion be obtained in regard to the characteristics of the materials 
in the strata. The presence of water and the effect of it on the 
various classes of materials met with have an important bearing 
on the success of the undertaking, and particulars relative thereto 
should receive special attention. 

For the purpose of ascertaining the character of the strata it ia 
usual to put down bores along the line of the railway or over the 
site of the works. 

Some Engineers consider that trial pits should be sunk, so as to 
get more complete information than is obtainable from bores. 

By the particulars so obtained the slopes for the cuttings are 
decided on and the quantities for the Contract Schedule calculated. 

The slopes in a cutting of ordinary material may vary from 1 
horizontal to 1 vertical, to 2 horizontal to 1 vertical, while in a 
rock cutting from a plumb face to f horizontal to 1 vertical, depend- 
ing on the character of the material, the quantity of water met 
with, the effect of water or atmospheric conditions on the material 
when exposed, and the slope or " dip *' of the strata. 

A description of the materials on the sites of the embankments 
is also essential for the purpose of ascertaining the bearing capacity, 
and fixing the quantity of material required for the embankments. 

If in cartying out the work there should foe any great dlvei^ence 
in the actual quantities of materials in the cuttings from what was 
stated ip, the Contract Schedule the method of procedure may 
p be i&odifed. 



10 EARTHWORK IN RAILWAY ENGINEERING 

As example, a cutting may contain considerably more rock than 
was at first anticipated, and on account of this it may be necessary 
to construct overland routes for the purpose of passing the material 
from other cuttings to embankments, and thus allow the oper- 
ations in the soft cutting to be proceeded with at the same time 
as in the rock cutting, or other special means may require to be 
adopted so that the work may be executed within a reasonable time. 

The fact of having an increased quantity of rock to excavate 
increases both the cost of the work and the time of completion and 
if definite information in regard to the strata had been forthcoming 
previous to the work having been commenced the Engineer might 
have considered a diversion of the route of the railway, or the 
promoters might have decided to abandon the project. 

When executing the widening of an existing railway it may seem 
sufficient to form an opinion as to the character of the materials in 
cuttings from the appearance of the existing cuttings. 

In the case of solid rock cutting no mistake may arise, but in the 
case of the ordinary soft material or materials of a "faikey"* 
character where the action of the weather may have very materially 
altered the adhesion of the particles or the surfaces to one 
another, it is not safe to rely too much on what is seen of the 
existing cuttings. 

In a case which recently came under the author's notice the 
slope of the original cutting had a batter of 1J horizontal to 1 
vertical, and to all appearance the cutting was of a clayey descrip- 
tion* On executing the work, however, the material met with con- 
sisted of close-bound gravel held together by hard clay, and was of 
such a character that it was quite impossible to remove it by pick 
and shovel On account of the situation it was not possible to use 
a steam digger, and it was necessary to break up the material by 
blasting throughout the whole period of the operations. After 
the material had been exposed to wet weather the clay lost all its 
cohesion and the slopes had to be dressed to the batter for an 
ordinary soft cutting. At several places in the slopes minor slips 
took place on account of the " weathering" of the material* 

In another instance of railway widening a number of large pieces 
of rock protruded from the slope of the existing cutting, which 
gave every indication of rock being met with, but OB. the wozk 

* Similar in, character to laminated shale. 



INVESTIGATION AS TO STRATA 11 

being carried out it was found tliat no solid rock existed and that 
a large number of loose stones were embedded in the slopes of the 
old cutting, so that the appearance of the original cutting was 
deceptive in respect of the actual condition of matters. 

In general practice boring is carried out by means of a chisel, 
samples of the material passed through being brought to the surface 
for inspection at intervals as the sinking operations proceed. Where 
more accurate information is required diamond drilling is adopted, 
in which case a solid core of the material passed through is 
obtained. 

By sinking pits the most reliable data as to the actual state of 
matters will be obtained, but the time taken in sinking pits of any 
great depth will, in most cases, be against this mode of procedure. 

Chisel boring is a very simple operation, and when the work is 
in the hands of a thoroughly skilled and trustworthy borer very 
satisfactory results are obtained. 

In chisel boring, owing to the importance of the information 
required, the work should be carried out by a reputable firm of 
borers under the direct supervision of the Engineer, who should 
keep himself fully conversant with the progress of the operations, 
and have repeated checks made of the depths of the strata entirely 
independent of the journal with which the borer afterwards furnishes 
him. He should also verify the depth of each bore immediately after 
it has been put down to the required depth. The borer should lay 
out for inspection samples of all the various strata passed through. 
By adopting such means the information so obtained will be as 
accurate as is possible by this method. 

It is unnecessary to describe in detail the whole procedure of 
chisel boring, and only a brief reference to the tools and the manner 
of use will be made. The bore hole is formed by repeated blows 
from a chisel (c) which is raised and lowered by manual labour (see 
Big. 4). The tool is turned round in the hole a quarter of a circle 
after each stroke is made so that no two blows fall in succession 
on the same spot, and the material, after being thoroughly 
bruised, is brought to the surface by means of a "sludge" 
pwip (/). 

In passing through ordinary soil, sand, city without stones, 
or similar material the sharp edge of the tube of the pump 
is, saffidbit to pierce the strata, but where gravel* bojddgnH aac 



12 



EARTHWORK IN RAILWAY ENGINEERING 



rock are met with the chisel is required. Where the material is 
exceptionally hard the cross-shaped piece, or " riffle " tool (e), is 
used. 

The cutting tool is connected with the cross-head on the 
working platform by means of 1-in. square section rods, which 



PlatPgrm 



Ground 



(3) 



Leve!^ 




Level 



T 
II 




(f) 



(*) 



Q 



4* OMsl boring. 



are generally in lengths of 5 ft. and screwed together as shown ; 
shorter lengths being used when each of the 5-ffc. lengths ha 
brought the crosa-head down to the level of the working platform* 
The pktf orm should be at a height of about 5 or 6 ffc. above the 
ground so as to allow erf tubing b^rog inserted into iba bow 



INVESTIGATION AS TO STRATA 13 

when passing through, soft ground and where the sides of the hole 
would have a tendency to fall in unless properly supported, in which 
case an inaccurate record would be obtained. It is necessary that 
the tube should closely follow the cutting tool as the work proceeds. 
Of course, in rock no tube lining is necessary. 

If the strata should be dry it is essential that water be poured 
down the tube for the purpose of converting the material into a 
consistency of slurry and thus allow of it being removed by the 
" sludge '* pump. In order that a correct record may be obtained 
samples of the strata should be brought to the surface at least 
every 2 ft. of depth. 

All depths should be measured from the level of the working 
platform, the height of which above the level of a wooden peg or 
mark on the ground level should be known before boring opera- 
tions are commenced. The level of the peg or mark should be 
connected with Ordnance Survey level or the same datum to 
which the sections for the railway have been taken, so that after 
the journal of bores has been completed the information obtained 
can be laid down on the sections of the ground surface. 
Three or four men are usually employed in sinking the bore, 
one of them being a practical borer who would be responsible for 
the preparation of the record. While the contents of the " sludge " 
pump indicate the character of the material passed through, the 
borer puts considerable reliance on the *' feel " on the cross- 
head. 

When boulders are met with, if the boring tool comes down fair 
on the top of the stone, there will be no difficulty in passing through 
it, but if the tool strikes the smooth rounded surface away from 
the top, the stone will yield in the surrounding clay and it will 
be nexi to impossible to pierce it. In such case a small charge of 
dynamite should be inserted in tke bore and the boulder shattered. 
If this is not efleotive it wil be necessary to abandon the bore and 
sink another a short distance away. 

All the bruised material, whether haxd or soft, is brought to the 
surface in the Mate we1 condition and it is only by the " feel ** 
when sinking and the rate of progress that the relative hardness 
of Hie material is ascertained It is necessary tfeat the ptimp be 
pit down at eveiy 2 ft* f and m< frequently if necessary, if a change 
of stratum is suspected by the " feel " on the cross-head. It will 



14 EARTHWORK IN RAILWAY ENGINEERING 

be recognized that the borer, in addition to having a thorough 
practical knowledge of his business, must exercise considerable 
care in systematically noting the various changes of material if 
the results obtained are to be of any real practical value. 

A very common error, and one which has frequently been the 
cause of much litigation, is to mistake a boulder in a " soft " 
stratum for solid rock. The effect of this may be very serious. In 
the case of a railway or road cutting, by assuming that rock has 
been reached when only a boulder has been struck the quantity of 
material which it is anticipated has to be excavated may, as already 
stated, be considerably in excess of the actual quantity to be 
removed and this may have serious consequences. 

When rock is met with, before it is recorded as solid rock, the 
thickness passed through should exceed 5 ft. If this depth is ex- 
ceeded it is pretty safe to assume that a bed of rock has been 
passed through, but if not, a, new bore 6 or 8 ft. distant should be 
put down as a check, and if the strata is repeated it is evident 
that a layer of rock exists. The depth of a bore hole should never 
be less than 5 ft* below the bottom of the proposed excavations^ 
whether in " soft " or in " rock," so that the fullest inforDoaii^i 
may be obtained of the material to be excavated and also of tibe 
character of the strata below formation level of the railway on wMch 
it is proposed to support the foundations of structures* 

Hard-bound gravel can be easily distinguished from loose gravel 
and the various degrees of hardness of faikes and limestone can 
also be easily recognized, and where water is in a strata its presence 
can be detected. The volume of this water a point which is of 
very great importance when carrying out constructional work 
cannot, however, be computed by boring. 

As regards diamond boring, this method is now generally adopted 
where it is of advantage to have a solid core of rock, such as in 
mineral prospecting, and in locating the site of a reservoir embank- 
ment, where It is of great importance to know the character of the 
stratification below the submerged area. In the ease of tunnel 
work, or where heavy foundations are in rock, the results obtained 
from diamond boring would be preferable to thoBe obtained by 
chisel boring* The result of the bore cannot be questioned whea a 
solid core of rock can be seen, and the oomeqtMat risk of error i& 
judgment on the part of the bate* fe tibembj 



INVESTIGATION AS TO STRATA 



15 




In diamond boring the material is cut through by abrasion 
instead of by percussion, as is the case in chisel boring. 

The cutting tool or 6S crown " consists of a mild steel cylinder 
on the lower surface of which carbonados 
(imperfectly crystallized diamonds) are 
studded at intervals (see Kg. 5). When 
the bore is being taken for mineral pros- 
pecting or for the purpose of ascertaining 
the character of the strata for earthwork 
operations the core of rock need not be 
more than 2 or 3 in. in diameter. The 
" crown ?J piece would be about J in. 
thick and a set of twelve diamonds is 
distributed over the lower, outer, and 
inner surfaces, as shown on the diagram, 
so that the bore hole which is formed will 
be slightly greater in diameter than the 
cylinder in which the diamonds are set, 
and the core of rock which is cut out will 
be slightly less in diameter than the 
internal surface of the cylinder. The 
diamonds are so arranged that the ring 
of material cut through between the 
outer and inner edges of the cylinder 
will be entirely crushed. 

The core 9 after being cut, passes up 
through the " crown ** cylinder into the 
core tube, which is about 6 ft. long and 
which is screwed on to the upper end 
of the cylinder* This tube in turn is 
attached to hollow iron rods of convenient 
length which extend to the surface of the 
grornid. The tool i& caused to revolve 
either by hand labour or by being con- 
nected to a stationary engine. jjTj 

It is necessary while the boring oper- 
ations are in progress tbat a constant and ample topply of water 
fe forced clown the hollow rod &ad thKnagli the oom tube so that 
materiiil tmdcr the cutting edge will be ii 




a. &" Crown *' of 
diamond drill 



16 EARTHWOBK IN RAILWAY ENGINEERING 

washed out, the water rising up the outside of the core tube and 
flowing over the bore hole. The water also assists in keeping the 
cutting tool cool. The tool is caused to revolve at a speed of 
from 60 to 100 revolutions per minute, depending on the character 
of the materials passed through. 

It is most important that the crushed material under the cutting 
edge be instantly removed, as otherwise the metal in which the 
diamonds are fixed Will become worn and the diamonds wiU drop 
out. The pressure on the rock under the cutting edge should be 
relieved as the work progresses by having a back balance weight 
fixed to a cross-head at the surface. 

While diamond boring gives the true character and exact thick- 
ness of the various beds of rock passed through, it is not possible 
to say in which direction the rock is dipping, but by taking a series 
of bores a correct geological section can be prepared. 



TKIAL PITS 

Trial pits would be 5 or 6 ft. square. If the excavations are 
material it would, unless the pits are comparatively shallow, be 
necessary to close timber the sides of the openings. If the stratum 
is rock, timbering would not be necessary. Operations would b^ 
retarded if water were met with, and if it should be of considerable 
volume it may be impossible to proceed with the work. In bad 
ground or where there is a large volume of water iron cylinder, 
consisting of built segmental sections with flange joints, would be 
used. 

While the time occupied in sinking trial shafts is considerably 
more than that taken by putting down bores, the information 
obtained gives a mote correct indication of the strata passed 
through. Trial shafts at intervals supplemented by a series of 
bores to ascertain the levels of the various beds and thereby find 
out if there is any exceptional variation in the strata would provlda 
a full knowledge of the geological conditions* 

Trial shafts or bores are of no practical value unless they are 
carried down to the full depth of the proposed excavatieas^ or f in 
the case of foundation work, to the depth of a solid statum- 

Aa regards the rate of progr&s* m boring* the f oEoirog 
give a rough approximation ; , 



INVESTIGATION AS TO STRATA 17 



WITH HAND CHISEL BOBINQ 

Fine sand or clay without stones . . . 50 ft. in 8 hrs. 

Boulder clay or open gravel . . . . 20 ft. 

Close-bound gravel . . . . 6 to 8 ft. 

Soft sandstone . . . . . 8 to 12 ft. 

Hard sandstone . . , . . 2 to 4 ft. 

Extra hard sandstone . . . . 1 ft. 

WITH DIAMOND BOBING 

Hard sandstone . . . , . 10 ft. 
Eztra hard sandstone . . . . 5 ft. ,, 

When hard whin boulders are met with in boulder clay it is no 
uncommon thing for only a few inches to be pierced by chisel 
boring in a day's work. 

While the chisel is the tool generally in use for boring in this 
country, the " wash-out " drill, which, as the name implies, con- 
sists of the material being washed out by water under pressure, 
is largely used in America. The record so obtained in passing 
through soft material is not considered very satisfactory, but the 
advantage in using this system is the rapidity in clearing a way 
for a diamond drill being used in the rock underneath, 

In describing the strata passed through a Borer should tefrain 
from making use of any local expression which may be ambiguous 
or misleading, and the Engineer, when preparing the journals which 
are to be shown to, and will be made use of by, the Contractor, 
should make certain that the description which he gives is in 
general terms and correctly sets forth the class of material so "that 
no subsequent misunderstanding may arise as to the character of 
the materials in the bore. 

While it may not be absolutely necessary for a Borer or MI 
Engineer to have a knowledge of geology there is no gaiasaying 
the fact "that only by a thorough appreciation of the diaracteri^tics 
of the materials generally met with and their relative positions 
to one another in the strata, together with the conditions und&t 
which they have origmaUy been deposited, eaa he form a correct 
opinion of the materials he is dealing with. 

KJUfc O 



CHAPTEE III 
CULVERTS AND DEAINAGE 

THE situation of a line of railway, relative to rivers and principal 
waterways, is an important consideration in determining the 
location of the proposed works. The larger rivers and waterways 
would be crossed by means of bridges or viaducts, and do not 
come under the present investigation. 

In crossing streams or water-courses of less magnitude the pro- 
vision which requires to be made must receive due consideration 
in designing and carrying out the works. Local deviations of the 
line of the railway may suggest themselves with a view to leas 
costly, while equally efficient, conduits or culverts being constructed j 
without materially affecting the cost of the earthwork or other 
works. These may result in a shorter length of waterway or in a 
more solid foundation being obtained, or what is of considerable 
importance during construction, a line may be got which will aUo^f 
of the greater part of the operations in constructing the waterway 
being executed with a minimum of interference with the original 
water-course, and thereby in comparatively dry ground. 

By taking the water channel whether in tunnel or open-cut 
through a spur of rock the excavations may be more costly to exe- 
cute, but by reason of a shorter length of channel being obtained 
less masonry will be required for facing the excavations &nd in 
constructing the arch and invert, and the total cost may thereby 
be considerably reduced. 

It is of the utmost importance when making a railwaj that all 
work connected with the constraction of culverts or waterways, or 
the drainage of the adjoining lands, be entirely completed before 
the earthworks in the vicinity are proceeded with, so that slips, 
by reason of water flowing through the strata into the cuttmgs or 
under the site of the embankments, may be reduced to a, amttimtim. 

The capacity of a culvert or waterway should be snob m will 

IS 



CULVERTS AND DRAINAGE 19 

allow of the free passage of water during the period of maximum 
rainfall. Careful observations should be taken of the flow in the 
stream during wet seasons and flood-times and information should 
also be obtained from old residents in the district. By comparing 
these particulars with records of rainfall taken during previous 
years, if such are available, an approximate idea of what may be 
expected will be obtained* Where there are existing culverts or 
bridges on the streams which are being dealt with the effect of the 
flow of water on these and their capacity to deal with the quantity 
pf water passing through them should be noted. 

Apart from any information so obtained it is desirable that the 
size of the culvert required to carry important streams under the 
railway should be ascertained by calculation. The determining 
factors are, the maximum rainfall in the district, the area of the 
water-shed, the slope of the ground from which the water dis- 
charges, the porosity of the soil, and the condition of the stream 
or river bed. Various formulae are in use, but it will be recognized 
that the local conditions referred to make a universal application 
of a formula for the " run-off " impracticable* 

There will be a much greater discharge from an area with steep 
sides than from a flat basin. The more impervious the surface of 
the ground is the greater will be the discharge, but it should be 
borne m mind that some soils will be rendered impervious after 
a few hours* heavy rain, at the end of which time the soil may be 
aaid to be water-logged. A wet marshy ground might be described 
as water-logged and will yield a large " run-off " in a heavy rain- 
storm. 

A good formula for ascertainmg the discharge from catchment 
areas, given in Parkers " Control of Water/* is : 

Q640F.LM.* 



** discharge in cubic feet per econd. 

Average intensity of max. rainfall in inches per hour during a 
period of time equal to that taken by the flood water to reach 
the culvert from the farthest point of the drainage area, 
M aw Area of catchment arm in square miles. 

F is a coefficient dependixng on the character of the surface as follows : 

For flat country* sandy toil, or cultivated land, 0*25 to 0**&5 
For meadows and gentle slopes, OH5 to 0-45. 

1 This formula is sometimes given : Q=640 F 



20 EAETHWOEK IN EAILWAY ENGINEERING 

For wooded hills and compact or stony ground, 0*45 to 0*55. 
For mountainous or rocky ground, or non-absorbent (eg. frozen soil) sur- 
faces, 0'55 to 0-65. 

Apart from the results obtained by the use of a formula an ample 
margin should be provided for extraordinary floods. Some Engineers 
double the result obtained by a formula, and in view of the damage 
which may result from having a restricted waterway and the small 
increased expenditure incurred in providing the larger culverts as 
compared with the cost of the whole railway undertaking this 
seems a proper course to adopt. 

The late Dr, Deacon, when investigating the rainfall in the Welsh 
mountains in connection with the Liverpool water supply, ascer- 
tained that the maximum discharge of tributary streams commonly 
reached 1000 times the dry weather flow, and occasionally in- 
dividual streams very much exceeded that figure. In the Vyrnwy 
River, even after passing over from four to five miles of alluvial 
deposit, the maximum discharge recorded as much as 800 times 
the dry-weather flow of the river, and the records obtained from 
rain gauges which were within a few miles of one another showed a 
very considerable variation in rainfall. 

It is thus most important that information regarding the flow 
of water in streams should be localized as much as possible, and 
that the capacity of the culvert should equal the discharge from 
extraordinary floods. The probability of there being excessive 
flooding by reason of melting snow should be specially noted. 

Allowance should be made in designing culverts for the possi- 
bility of the effective sectional area being reduced by becoming 
silted up. This will be greater if the stream has a flat gradient, as 
under ordinary circumstances the flow in it will be sluggish, 

In new countries where records of rainfall are not obtainable it is 
usual to construct temporary timber bridges or rail openings which, 
are in use for a few years until it is seen what provision requires to 
fee made in constructing the permanent culverts. 

In hilly country a large quantity of embaaking material is 
generally lost on account of sudden and heavy floods before it in 
possible to judge what sim of openings should be provided, and the 
embankment on each side of these water openings should be well 
protected by having stone pitohtag carried up the slopes aa Mgfa, 
as the probable flood leveL 



CULVERTS AND DRAINAGE 21 

Where there are wide depressions of land in countries subject to 
heavy rainstorms, over which during the period of floods a large 
area of flood water flows, it is usual, provided the water is shallow, 
to let it pass over the line altogether (see Fig. 6). This is effected 




Lancjitudlns? Section of Railway 




Cross Section of Railway shewing 

Pitching of Embankmenb 
FIG. 6. Water openings in embankments. 

by forming the line on each side of the depression with an easy 
grade down to a level portion, which level portion might extend 
to from 100 to 400 ft. in length, as shown in the diagram. For the 
purpose of protecting the railway and the slopes on each side and 
between the sleepers, the surface would be covered with stone 
pitching which would extend for the whole length of the level 
portion and up the gradients to a level clear of flood level. 

DESIGN Qtf CULVERTS OB WATER-COURSES 

It is of the utmost importance that the construction of culverts 
and water-courses, where they pass under embankments, should 
be of a most substantial description in view of the expense and 
inconvenience incurred in opening up embankments for the purpose 
of executing remedial work. 

Existing conduits on the site of the embankment should be 
strengthened or reconstructed. When pipes are used for the pur- 
pose of carryiag the stream, they should preferably be of iron or 
steel, and if they are not laid on aoHd ground they should be sup- 
ported on masonry piers or piles. On account of malleable iron or 
steel pipes being ligliter than those of cast iron they can be made 
in longer kngths and consequently fewer joints are necessary. They 
also less liable to iujury than cart-Iron pipes* 

In soft groTd or where there* is a tencltocy to subsidence by 



22 



EARTHWORK IN RAILWAY ENGINEERING 



reason of mineral workings malleable iron or steel pipes are prefer- 
able. The smaller weight per unit of length is also a consideration 
in cases where it is necessary to drag the pipes over fields or convey 
them long distances over secondary roads. Malleable iron or steel 
pipes, however, are more subject to corrosion than cast-iron pipes, 
and care should be taken to ensure that they are properly pro- 
tected by preservative coatings or by having them encased in 
concrete. 
Where fire-clay pipes are taken under a railway they should be 






FIG. 7. Fire-clay pip drains u&der railway* 

encased in concrete (see Fig. 7). When concreting materials can 
be economically obtained a fire-clay pipe conduit is in many cases 
adopted in preference to cast iron, more especially in the smaller 
diameter of pipes. 

In conveying water from one side of a railway embankment to 
another when crossing bog-land, timber box drains are generally 



* Jit 




? -Bolts 



12x3' 



S'O 







} Z < 3 * /2*3'/ 

Cross Section Longitudinal Section. 

Fta. 8. Timber box drain under railway. 

used (see Fig. 8). While these may be considered to be more of a 
temporary character, if they are constructed of creosoted pitch-pine 
timber they wiH last for a number of years, and in th& particular 
situation where they would be used they ate easily accessible when 
they require to be repaired or renewed* 

For conduits of a less size than 2 ft* 6 IB* square, and where pipes 
cannot be conveniently used, built ston draias are eonstrueted 



CULVEETS AND DRAINAGE 



23 



(see Fig. 9). These consist of a floor of concrete with masonry walls 
built with cement and covered over with a slab or paving stone. 
The cover stones should be well bedded on the top of the side walls 





Stone Slab* 
Pavrnp Stone 


X 


Stont 


J 






Concrete ^ 











i 




Concrete 



(6) 



a 

6 








/-8*-* 


1 9 


/ t 

*/ 6^ 


+ 2'-0?L 


^/a% 


-5 



(c) 
Fia- 9. Built g(tone drains under railway. 

and close jointed with cement mortar in order to prevent banking 
material finding its way into the culvert. 
When the volume of water in a stream is greater than a 2 ft. 6 im 





Arch cufowts tmdar railway. 



drain oan carry masonry built oolverte are adopted (see Fig, 10). 
These generally have an arched roof and are either wholly of con- 
crete or are ooasteuoted partly of cxmcocele aad partly with stone 
or bricfcwork. The partioukr material u^l win be gov^m^d by 



EARTHWORK: IN RAILWAY ENGINEERING 



the facilities for obtaining them. Ferro concrete construction is now 
largely adopted,, having either a rectangular or arched section. To 
ensure satisfactory results, however, it is absolutely essential that 
the materials used should be of the best description and also that 
every care be taken in the making of the concrete. 

Riveted malleable iron or steel tubes are sometimes substituted 
for built culverts* These can be obtained up to 6 or 8 ft. in diameter, 
and, being accessible for inspection and for painting or coating with 
preservative solution, they may, if proper attention is paid to the 
maintenance, be said to be equally as efficient as a masonry culvert. 
If one line of tubing is not sufficient to carry the stream two or 
more could be laid alongside one another. 



(Concrete 





Cross Section. Longitudinal Section, 

Fia. 11. Culverts with steel beams and concrete covering* 

When the headway above the bed of the stream where it passes 
under a railway or road is limited, the roof of the culvert could 
be formed with steel beams and concrete filling between them, or 
slabs of concrete with steel reinforcement could be used (see Fig. 11). 
These can either be built in lengths on the solid ground alongside 
and afterwards lifted into position, or the reinforced concrete can 
be formed in situ by placing timber between the side walla. The 
former method has the advantage that less timber is necessary, but, 
on the other hand, additional lifting power is required to place the 
slabs in position if they are made on the adjoining ground. 

When a culvert requires to be constructed in very side-lying 
ground and where there would be considerable flow the invert should 
be left rough, and, in this connection, whinstone pitching is largely 
used. In open channels, in addition to whimstone pitching being 
used for the purpose of checking the flow, some of the pitching 
stones can be set on edge at intervals and made to project above 
the surface to the e:rtent of about 6 in., the object being to farther 
reduce the velocity of the current 



CULVERTS AND DKAINAGE 



26 



A series of steps at the end of a culvert would fulfil the same 
purpose, or a well or pool about 4 ft. in depth could be formed 




into which the water would discharge before getting into tibia 
regular course of the stream (see Mg* 12). 
When a line of pipes is kid on side-lying ground the pipes should 



26 



EARTHWOBK IN RAILWAY ENGINEERING 



be supported by small masonry piers which, in the case of cast-iron 
pipes, would be placed on the lower side of the faucets, or the joints 
can be encased in concrete, as shown in Fig* 12, while if malleable 
iyon or steel pipes are used the pipes would be held in position by 
having metal straps riveted to the tubes at intervals, the ends of 
the straps being embedded in concrete blocks. Any movement 
in the pipes would be attended with very serious results to the 
embankment overhead. 

In the case of a culvert built on. sloping ground the foundations 
should be laid on level benches while the water-run would either 
follow the grade of the side-lying ground or could be stepped, and 
if the ground has a very steep slope the arch would also be built 




Fio. 13. Stopped arch culvert on side-lying ground. 

in level sections (see Fig. 13). The level crown, while allowing of 
level beds being formed in the masonry, would also act as a support 
to, and prevent slipping of the embankment. 

Where culverts are constructed on soft ground they should be 
carried on piles and built in lengths of from 20 to 30 ft,, each length 
being entirely disconnected from the adjoining one except for a 
cement joint, the idea being that in the event of unequal subsidence 
taking place by reason of the weight of the embankment on the top, 
the culvert will not be subjected to the same risk of damage. In the 
event of subsidence taking place the joints between the various 
lengths can be made good. Even i& good ground except solid 
rock it is well to build the culvert in sections when 
high embankments, as there wiU be subsidence, however 
due to the weight of the embankment on th strata mdc the 
culvert. 



CULVERTS AND DRAINAGE 27 

This suggests that culverts under high, embankments should be 
milt with a vertical camber, as is sometimes done to allow for the 
rarying subsidence which may be expected from the greater weight 
inder the centre of the embankment. If the culvert is constructed 
m the level and subsidence takes place the hollow in the centre will 
Become silted up and the effective water area will thereby be 
Deduced, 

In fixing the line of a culvert under an embankment it is better 
;hat it should be constructed by cutting into the sloping ground 
>n one side of the natural run of the stream and thus have a 
smaller side surface area exposed to the pressure of the made-up 
embankment, as at Section B, Fig. 15. There would also be less risk 
rf damage to the culvert by reason of any slipping of the material 
3f which the embankment is composed. 

The length of culverts under high embankments should be such 
5ts will allow of the slopes of the embanking material taking the 
aatural angle of repose. The invert of the water channel between 
bhe walls at both ends should be pitched with stone, and at the 
inlet end the pitching should be laid on a bed of concrete made 
continuous with the concrete foundation of the inlet walls. A 
concrete apron should also be formed at the inlet end for the pur- 
pose of preventing the invert of the culvert being undermined by 
flooding, as shown in Fig. 12* 

Culverts and waterways should be protected by having a grating 
placed at the upper end to prevent debris or floating branches of 
trees choking the culvert and obstructing the flow. These gratings 
or gates should be placed far enough back from the entrance to the 
culvert as not to reduce the available area of the waterway or in 
any way obstruct the free flow of water into the culvert. 

Special attention should be given to the design of the ends of the 
culvert in order to obtain a maximum efficiency (see Fig. 14). The 
best results are obtained when the inlet has a bell mouth shape 
and where the approach channel is at the same level as the invert 
of the culvert. All ob&traction by fomnrkg corners in the masonry 
should be avoided. The most objectionable form 6f inlet would be 
to have the walk at right angles to the line of the culvert as at (A), 
i%. 14, in which case the water entering the ctilvert forms an eddy, 
wMct is a serious obstruction to the free flow. The walls at the 
omifefe end ahotild be carried straight out in the Hue of the culvert or 



28 EARTHWORK IN RAILWAY ENGINEERING 




inlet End Elevation. 




Outlet End. Elevation. 




1 



Inlet End. Plan. 



Outlet End Plan, 




inlet End. Section AA* 



Inlet End. 



(A) 



Fro. 14.-- Design of ends of culverts, 



CULVERTS MTD DRAINAGE 



29 



bell-mouthed the same as tlie inlet end so as to take the water 
clear of the culvert. 

Culverts should, wherever possible, be straight and have a uniform 
grade throughout. 

Under certain circumstances it may be possible to convey water 
from two or more water-courses into one culvert and thereby 
reduce the number and length of culverts under the railway or 
road (see Fig. 15). Where it is necessary to take the waterway in 



Hand-set Whinsbwe 

grouted^ 
withCet ' 

Wan 
Section A. 




flMfllfi 1 ^ 




Sectfon 8 
Fro. 15. Two water-courses conveyed in on culvert under railway. 

an open channel alongside a railway embankment the bottom and 
sloping walls of the channel should be pitched with hand-set stones 
and grouted with cement to prevent damage to the railway embank- 
ment. 

In constructing culverts under embankments it is a common 
practice to place them in the line of the water-course at the 
bottom of the vaUey to be crossed and consequently at the highest 
and widest part of the embaaalonent. In tikis situation ike 
culvert may i>0 of eoBBidarable langti, and the first cost of it. 



30 EARTHWOBK IN RAILWAY ENGINEERING 

as well as the subsequent maintenance will form an important 
item. Where the ground is comparatively flat there may be 
no alternative, but where it is side-lying and where the 
stream has a rapid fall it may be possible to divert the water- 
course on the upper side of the embankment and carry it in open 
cut or built culvert with very little cover along the contour of the 
sloping ground and with just sufficient fall to properly carry away 
the water and thereby cross the railway at a much narrower point 
(see Fig. 16). By doing so the length of the portion under the rail- 
way or road may be very considerably reduced and the part of the 
conduit in open channel or built culvert would be easily accessible 
for the purpose of repairs or for the cleaning out of debris which 
might be washed down. It would, of course, be better that the 
whole length of the approach conduit should be in open channel, 
but this may not be possible. 

If it can be arranged to have the crossing of the railway or road 
at the junction of the embankment with the adjoining cutting, 
the length of the covered channel would be reduced to the width 
of the formation of the railway or road. The pressure on the arch 
or upper surface of the culvert would also be reduced to a minimum 
as the load would only be that due to the weight of the material 
of which the railway or road surface is constructed, with in addition 
the live load due to the traffic passing over it. 

If the stream or water-course is diverted in a manner similar 
to what has been indicated, the level of the discharge end of the 
waterway will be considerably higher than the original course of 
the stream, and it will thus be necessary to construct a series of 
steps in the part of the channel on the low side of the railway to 
break the flow of the water, as shown on the diagram, over which 
steps the water would discharge. If the ezcavations should be in 
rock, the discharge would be over a rocky surface and no building 
would be necessary in forming the water channel* 

When diverting a stream from its original course it is necessary 
to guard against the forming of abrupt corners in the altered 
channel, which would cause an obstruction to the flow of water, 
and an endeavour should also be made to liave the altered channel 
constructed so that the flow at the point where it connects with 
the original course will be as nearly as possible what it was previous 
to the stream being interfered witib, m otherwise damage by flood- 



,Ai^ 

x^%. 

\\<-<> x 

l\ \-^ -"1 

\% 

% S <^A 

\ V--^ 



^ 



' 




SeotJonC.C.C. 
16. Water chtamel diverted along contour of sloping ground. 



32 EARTHWORK IN RAILWAY ENGINEERING 

ing may result to the lands either higher up or lower down the 
stream than the site of the culvert. 

In order to prevent the lodgment of water on the upper side 
of the embankment between the level of the diverted water channel 
and the original level of the stream where it passes under the bank, 
the ground should be made up to the level of the diverted water 
channel if this can conveniently be done, as shown in Fig, 16, the 




Seeton A.A Section 8,8 

Fra. 17. Road and stream diversion carried under railway at on place. 

embanking material used for the purpose being weU consolidated 
so as to prevent surface water damaging the embankment. 

If the filling up of this area is too extensive an operation It will 
be necessary to lay a pipe or construct a small culvert tinder the 
railway embankment to drain this ground. 

Every care must be taken in diverting the water-bourses to see 
that there is no drainage left along the original course under the 
railway embankment, as serious damage may result ttemgh the 
material becoming sodden and slips taMrig place* 



CULVERTS AND DRAINAGE 33 

Under certain circumstances it may be possible to take a road 
and stream under the railway at one place by a bridge as shown in 
Kg. 17. 

Where the water-course Is at a higher level than the formation 
level of the railway and has to be carried across the railway, it will 
either require to be taken under the railway in a syphon pipe or 
over it by means of a pipe or box conduit. A syphon would be 
adopted where there was not sufficient headway for railway traffic 
to allow of the conduit being taken overhead (see Fig. 18). The 
pipes forming the syphon would be of iron or steel and the joints 
made watertight, and the piping would require to be capable of 
withstanding the pressure of the head of water caused by the 
difference in level of the top and bottom of the cutting, in addition 
to any other pressure to which it may be subjected. 




Jb'iu. 18. Syphon pipe under railway. 

When the pipe or conduit is carried over the railway it would 
be supported on a trestle bridge,, or on a road bridge. 

If supported on a trestle, as at Fig. 19, there is a danger of 
drivers or firemen of trains meeting with accident when engaged 
taking coal from the top of the engine tender, owing to their 
not observing the pipe as clearly as they would the girder of a 
bridge. By reason of tMa 5 and also on account of the extra cost 
involved in constructing the piers and framework of a trestle it 
may be preferable to divert the water-course so as to cross the 
railway on an overbridge if there should be one near at haacL 

In Fig. 20 the pipe is shown earned over the railway on a road 
bridge, being supported on the outside of the main girders- 

If the wster-course m larger than can be conveyed in a pipe it 
eaa be taken across the railway in an open conduit (see Fig, 21)* 

The author has knowledge of a case where a. stream and farm 
road were carried over the railway on one bridge (see Fig. 22). 

Instead of conveying the water acrosa the railway by any of tibie 
described ife might be takaa down the slope of the cutting 

*~ D 



EARTHWORK IN RAILWAY ENGINEERING 






CULVERTS AND DRAINAGE 



35 



either in an open stepped conduit or in a pipe and led alongside the 
formation of the railway into a watercourse at tlie end of the 
cutting. This would, of course, necessitate the making of the 
formation of the railway wide enough to take the conduit in addition 
to what is required for the actual construction of the railway, and 
the additional cost involved might be prohibitive* 




FIG. 20. Pipe carried over railway on road bridge. 

Where a railway is constructed through a town, water, drainage; 
and gas pipes will have to be dealt with, and provision made for 
tihtem when designing the bridges carrying streets over the railway 
or other work. i* f 

The question of what drainage works are necessary for the pro- 
tection of cuttings and embankments of railways is dealt with in 
Chapter VI. 



Water 
Ji 



wofM stte/jwst 



. 21. 

earned orer railway 

in open conduit* 




Section A. 

FIG. 22. Stream and road carried over 
railway on one bridge* 



CHAPTER IV 
EXECUTION OF EARTHWORK 

FOE the execution of the work there will be a Specification, Schedule 
of Quantities, and Contract Drawings. 

SPECIFICATION 

The requirements of the Contract Specification are referred to 
in Chapter IX, and it will only be remarked here that so far as the 
descriptive clauses are concerned they should be as full as possible, 
both as regards the manner in which the work is to be executed and 
the quality of the materials used in construction* 



The general practice in preparing a Contract Schedule is to detail 
as fully as possible the various items and quantities of work to be 
executed in carrying out the work. 

Under the heading of " Earthwork " the quantities of materials, 
whether in road or railway cuttings and embankments, with their 
situation in relation to the mileage marked on the general plan and 
section hereinafter referred to, should be separately stated. 

Where there is rock in any of the cuttings there should be a 
separate item. 

The quantities of materials in each item of work in bridges, 
stream diversions, and culverts should also be scheduled in detail* 

Sewers and drains which will be distributed generally all over the 
work should be grouped together under one quantity for each 
item. 

Under the heading of ** Sundries ** there should be Included 
general work such as office accommodation, the setting out of workB, 
scafiolding, watching, lighting, etc, 

36 



EXECUTION OP EARTHWORK 37 

The Schedule when read with the Specification should leave no 
doubt In the mind of the Contractor as to the character and extent 
of the work to be executed. 

In so detailing the Schedule the Engineer furnishes the Con- 
tractor with all the information at his disposal, and the Detailed 
Estimate when priced, on which the Contract Tender will be 
based, will give, so far as can be seen when the work is let, what 
the actual cost of the undertaking will be. 

CONTRACT DRAWINGS 

The drawings with which a Contractor is furnished to enable him 
to execute the work usually consist o a general plan, a longi- 
tudinal section, a sheet or sheets of cross sections, and detailed 
cross sections giving width of road-bed or formation, depth of 
ballast or road forming, the size of side ditches or water channels, 
drains, etc. 

He will also be furnished with typical drawings of culverts and 
drains for the general drainage of the adjoining lands, and drawings 
of special culverts or aqueducts for conveying water-courses over or 
under the railway* The plans should be as complete as possible. 

GBNEBAL PI^AN" (see Fig. 23) 

The general plan is generally prepared to the scale of the Ordnance 
Survey of 25-344 ins. to a mile (m^Vo), or a somewhat similar scale 
if an Ordnance Survey does not exist, but where there are few divi- 
sions of land a small scale plan can with advantage be used. The 
plan should show the boundaries of adjoining properties, the centre 
line of railway, the boundary fences on each side, the radii of 
the curves, and the mileage measured along the centre line relative 
to a fixed point. 

The situation of the principal road and river diversions and 
how they are to be taken over or tinder the railway, culverts, 
and important water-courses crossing the railway, should also 
be indicated on the plan, and a reference should be made at 
each bridge or other work to the number of any detailed draw- 
ings of the same. Dimensions should be marked on the plan 
fixing the exact position of the straight portions of the railway 
irektive to easting buildings or fences. No mileage distances 



38 EAKTHWORK IN BAILWAY ENGINEERING 




EXECUTION OF EARTHWOKK 39 

should be given to the commencement or termination of the curves 
as the radii will determine their exact position on the straight 
portions of the line at each end. The positions of the boundary 
fences which are ascertained from the cross sections should also be 
indicated by dimensions from the centre line ; and so that the fences 
will be erected in uniform lines it may be necessary to modify 
somewhat the widths obtained from the cross sections* 



LONGITUBINAL SECTION (see Fig. 24) 

The longitudinal section will show a profile of the natural 
surface of the ground along the centre line and also the formation 
level of the railway. It should be plotted to the longitudinal scale 
of the 25-344 ins. to a mile 'Ordnance Survey, or to a somewhat 
similar scale, and to a vertical scale of 1 in. equal to 20 ft. It will 
be a convenience if the horizontal scale is the same as that of the 
scale of the general plan. The various gradients will be marked 
and also the height of formation relative to Ordnance datum at each 
change of gradient. 

For convenience of calculations in the field the gradients should 
if possible, be stated at a regular figure per chain (66 ft.), per 100 ft. 
or per 20 metres according to the particular measure of distance 
in use. 

- As in the case of the general plan, the mileage of the line should 
be marked on, the section as well as the position of principal 
bridges or culverts and a reference to more detailed drawings. 
While the datum line of the section may for convenience be above 
or below ordnance datum, all levels marked on the section should 
be the height in relation to ordnance datum. 

When fixing the lev$l of formation endeavour should be made to 
get the quantities of the materials in the cuttings and embankments 
to balance so far as is consistent with the character of the materials, 
keeping in vietr that eetiain quantities of the material may be 
suitable for building, road-mating, or other uses on the Contract, 
and alao th&t the exxmvated material wil not occupy the sanie 
volume in the embaiikment as in the cutting, and that an 
allowance will require to be made for bulking. As regards the 
allowance made for " WMng** of the exmvations, it fe usual to 
when preparing the Contract Setedute that tie 



40 EABTHWORK IN RAILWAY ENGINEERING 

in a thoroughly solid embankment -will occupy from 3 to 5 per 
cent more volume than it formerly did in the cutting. The 
" bulking " of rock taken by itself may be as much as 40 per cent, 
but as the quantity of rock in railway embankment is generally 
a small proportion of the whole, the figure of 3 to 5 per cent 
above stated may be taken as a fair average for all classes of 
material. 

Regard should also be had to the desirability of having the material 
from the cuttings run down the grade to embankment and with 
as short a " lead " (haul) to embankment as possible, and it should 
also be kept in view that the intervention of a rock cutting which 
will take longer to excavate than a soft cutting, or of a tunnel or 
viaduct will probably delay the excavations. For the more effective 
drainage of the permanent way it is also desirable that the line 
where through cuttings should have a slight fall to one or both 
ends of the cutting. At a change of gradient a vertical curve should 
be introduced so as not to have a sudden change when passing from 
one gradient to another. The maximum or ruling gradient will 
be influenced by traffic requirements, but it is necessary that the 
line where through stations, or where sidings join and where it may 
be necessary to have carriages or wagons standing on the Main 
Line, shall not be on a steeper gradient than 1 in 260. Where the 
horizontal measurements are in chains (66 ft.) it is usual to make 
this gradient 1 ft. in 264 ft. (4 chains). 

CROSS SECTIONS (see Fig. 25) 

The cross sections should be plotted to a natural scale of 1 in. 
equal to 20 ft., so as to correspond with the vertical measurements 
of the longitudinal section. For the purpose of ascertaining the 
quantities of material in the cuttings or embankments required 
for the contract schedule of quantities, and also for determining 
the position of the boundary fences, cross sections should be taken 
at 'every 66 ft., 100 ft. or 20 metres, according to the particular 
measure of distance in use. Cross sections should also be taken 
at intermediate points where the ground is irregular in order that 
the quantity of earthwork may be more correctly agcertained. 
For the Contract sheet of sections it is sufficient to give sections at 
every 3 or 5 chains apart, the object being to give the Contractor 
a general idea of the character of the work* The croaa sections 



EXECUTION OF EARTHWORK 41 

will stow the surface of the ground, the slopes of the cuttings or 
embankments which have been determined upon after considera- 
tion of the character of the strata obtained from the bores or 
trial pits previously put down, and the boundary fences will be 
placed from 7 to 10 ft. back from the top or bottom of the slope 
according to whether the line is in cutting or embankment. 

Another method is frequently adopted in this country and 
usually in America which would avoid the necessity of taking 
cross sections at every peg (except at points where the ground is 




Fia. 25. Contract crosls dectiona. 
(a) In. cutting. (b) In embankment. 

very irregular) and still give the same information, viz. side widths, 
edges of slopes, areas of cross sections, and cubic quantities of 
earthwork. 

Having completed taking the levels along the centre line and 
obtained the reduced level of each peg and of the formation level, 
the heights of embankments and depths of cuttings are known. 
The Engineer then proceeds to set out and drive the slope stakes 
opposite each peg, directly on the ground by means of a level, 
staff, and tape Hne. 

To illtMtrate the method (see Fig. 26) an embankment 10 ft. 
deep will be assumed, 30 ft. wide at formation, a&d having slopes 
of l|r to 1. The level is $et up conveniently on the higher side of 
the centre line, the stafi is held on the centre peg A and reads, say, 
12-50, The irtaffman then proceeds to some point B, which should 



42 EARTHWORK IN RAILWAY ENGINEERING 

be fully 30 ft. [15+ (10 x 1J)] from A since ground slopes downward. 
The horizontal distance A to B is measured and found to be 36 ft., 
and the staff reading at B is, say, 14-50. Assuming for the moment 
that B is at the bottom of the slope, the corresponding distance 
A to B can be calculated. Since A = 10 ft., therefore G D =2-5 ft. 
and BE= (14*5 2-5) =12 ft., i.e. the height from formation to 
assumed bottom of slope. The distance from A to B should therefore 
be (12 ft. xl|)+15ft.=33 ft., but as it was actually measured 36 ft., 
this at once indicates that the staffman must move back nearly 
3 ft. towards A. This is done and a second reading of staff at B 1 
is taken and same computation made. An expert staffman can 
frequently obtain the point with sufficient accuracy at the second 
shot. The bottom of the other slope is similarly obtained, and the 




FIG. 26, Fixing slope stakes. 

whole operation for one centre peg can be completed in com- 
paratively few minutes. The same plant for the instrument wiE 
usually be sufficient for several pegs on either side of it, 
* The areas can b readily obtained (see Fig. 27). The hatched 
area S T is a constant for each cross section, A is given, the 
horizontal distances A F' and A M' are measured and O can be 

ATT' v AO 
computed. The area FSOTM is therefore equal to ^ ..... :r:: + 

AM 7 x ACK AO AO 



_ - *__ ( A B"+A ]/)_ xF'M', and by deducting from 

this the hatched portion the area of the cutting is obtained, Since 
these areas are computed from actual field measurements it 
eliminates any error in plotting or scaling cross sections. 

A special form of field book ruled in columns is generally used 
for entering up both field work and computed areas and cubical 
contents of each cutting or embankment. 

There are columns for chainage, peg level, and formation level, 
also a column giving the height of formation^ above or below 



EXECUTION OF EABTHWOEK 43 

centre peg and slope pegs, and the distances of the latter from the 
centre peg are also noted. 

When a new line of railway is being constructed it may be advan- 
tageous to acquire sufficient land to allow for future widening, say, 
from a single to a double line, or if the line is at first constructed 
for a double line of railway it may be considered desirable to 
acquire sufficient land to allow of two additional lines of railway 
being subsequently provided for future developments. By doing 
so the land will no doubt be more economically acquired and save 
the inconvenience of having to obtain further Parliamentary 
powers or making additional agreements with landowners. Inci- 
dentally, it may be remarked that the extra width of land so 
obtained may be conveniently utilized for a service railway or over- 



K 

" 




FIGL 27. Area of cross section. 

land route for use during construction of the railway, which other- 
wise would probably have had to be constructed on land temporarily 
acquired outside of the boundary fences of the railway. 

The contract drawings for culverts and drains will be more or 
less of a general character, as the particular circumstances in each 
case can best be determined when the works are in progress. 

In works involving the construction of earthwork and masonry 
it is desirable that operations should commence in the early spring- 
time. It is thus important that the contract specification, 
schedule, and drawings should be completed some months pre- 
viously so that the Contractor may have ample time to prepare 
his tender and ako that the Engineer and Ms clients may be 
able to give due consideration to the Contract Tenders, and, 
further, that the Contractor may have full opportunity to mature 
his schemes for caorjong out the work and bringing forward plant 
and materials. By this means the work would be begun under 
tiie most favourable auspices aacl full advantage would be obtained 
of the best season of the 



44 EARTHWORK IN RAILWAY ENGINEERING 

SETTING OUT OF LAND AHD WORKS 

The first operation in the actual construction is the setting out 
of the land and works. Under the Contract Specification the 
Contractor is held responsible for the accuracy in position of the 
works, but in view of the possible legal questions which may subse- 
quently arise as to the boundaries of the promoter's property, it 
is better that the centre line and the boundary fences be marked 
off jointly between the promoter's Resident Engineer and the 
Contractor's Engineer without in any way prejudicing the pro- 
moter's position in the matter or relieving the Contractor of his 
responsibilities. 

The centre line of railway should be marked off by having pegs 
about 1 Jin* square by 15 ins. long driven into the ground at distances 
of 66 ft. apart, or other convenient length. "Where the line is across 
a rock surface chisel markings should be made or iron spikes driven. 

The distances along the centre line would be made continuous 
throughout the whole length and the mileage would be indicated 
on flat pieces of wood or stakes 3 ins. wide by f of an inch thick, 
placed immediately behind each peg. The straight portions of the 
line would be laid down accurately to the dimensions marked on 
the contract plan and the curves put in to the radii marked on the 
plan. The pegs on the straight portion would be ranged out by 
means of a theodolite between the fixed points laid down from the 
general plan, and the pegs on the curves by deflection angles from 
the tangent points, transition curves being introduced where 
required. The intersection points of the curves will in all prob- 
ability be outwith the boundary fences, and it is therefore most 
important that the tangent point at each end of the curves should 
be very carefully marked. This is usually done by having a larger 
peg for the tangent points and placing a smaller one on either side 
transversely to the centre line* The tangent points should be 
transferred to other pegs or fixed points in the line of one of the 
boundary fences, the distance to the same being entered in a setting- 
out book specially used for the purpose* 

All measurements taken in connection with the filing of the 
centre line or transference of the marks should be made with a 
steel band tape, and for setting out purposes a 0~ibu theodolite ia 
very suitable both for accuracy and for convenience in use* For 



EXECUTION OF EARTHWORK 




\t I _ 

ll ? I 

flu: 



1 



46 EARTHWORK IN RAILWAY ENGINEERING 

approximate determination of intermediate points on a curve the 
method of chords and offset measurements may be used, but the 
exact position of any point either on a curve or straight should 
only be determined by means of the theodolite. 

The levels of the centre line pegs should thereafter be taken, and 
a working longitudinal section prepared (see Fig. 28) on which will 
be marked the level of each peg, the calculated formation level of 
the railway, and the depth of cutting or height of embankment 
below or above the level peg. It is usual to indicate the peg and 
formation levels in black figures, the depths of cuttings in red, and 
the heights of embankments in blue figures on the working 
section. 

When the railway covers a large tract of country a small scale 
map, preferably 6 ins. to a mile ordnance, with the cutting and 
banking materials indicated along the centre line in red and blue 
colours respectively, is very useful for general purposes in locating 
the site of the works. 

When the centre line has been finally laid down on the ground, 
the boundary fences should be pegged out from measurements 
previously marked on the general plan. The enclosing of the 
promoter's property by the erection of walls and fences should 
be entirely completed before any of the other constructive works 
are proceeded with, and with a view to protecting the centre line 
pegs it is desirable that the boundary fences should be erected as 
soon as possible after the position of them has been marked off. 

Previous to constructional operations being proceeded with at 
any section, each of the centre line pegs for the length to be inter- 
fered with should be carefully transferred to fixed points on the 
boundary fence, so that their original position on the centre line 
can be obtained at any time as the work progresses. The levels 
of the pegs should also be transferred. These transfer pegs should 
for convenience be placed all to the one side of the centre line, 
and the particulars of situation and level should be noted in tke 
setting-out book. 

Considerable inconvenience and expense to the Contractor is 
incurred when it is necessary to remove only a few inches of material 
from the slope of a cutting after it has once been dressed off to 
a regular batter, and it is thus most important that the information 
furnished by the Contractor's Engineer should be strictly accurate. 



EXECUTION OF EAETHWOKK 47 



CONSIDERATION OP GEKEKAL SCHEME OF OPEBATIOHS 

Before proceeding with the actual operations on a contract of 
any considerable magnitude the Contractor should carefully con- 
sider the manner and order in which he proposes to execute the 
whole \york and the various portions of it. He will have looked into 
this matter in a general way when pricing his Schedule, and when 
the time limit within which he promised to execute the work 
was under consideration ; but in -view of the short time generally 
allowed to prepare his Tender the modus operandi will require to 
be revised, and the whole question again gone into, 

In contracts of other than the smallest dimension, it is unusual 
to enumerate in detail the minor works to be executed, such as 
provision of drainage of adjoining lands, the carrying of small water- 
courses over or under the railway, the diversion of gas and water 
pipes or electric cables, the construction of roads and bridges 
necessary for the accommodation of the lands intercepted, etc. 
While the greater number of these works are necessary for the 
proper execution of the undertaking, certain of them will require 
to be determined by agreement with the proprietors of the land 
passed through, or with public bodies, involving legal formalities. 
The time so taken up, together with that occupied in the 
preparation of special drawings, would very seriously delay the 
commencement of a contract if it were necessary that these should 
be finally decided upon beforehand. The Contractor must, there- 
fore, keep in, view the probability of such works being necessary 
and his operations should be regulated accordingly. 

In terms of his Contract Specification, the Contractor may require 
to take the whole risk of the materials in the excavations or under 
-the sites of the embodiments proving different from what lie 
anticipated. While the journal of bores which the Engineer has had 
prepared previous to the Contract Schedule being niade tip, and 
to which the Contactor has access, may correctly represent the 
character of the Bmteriafe in the strata at the points where the bores 
were put down, in view of the importance of the matter, the Con* 
tractor may think it desirable to obtain further information by 
puMiag down additional bores, or sinking trial pits. If he decides 
to dp -.so lie wotald put tibe work in hand Immediately after getting 



48 EARTHWORK IN RAILWAY ENGINEERING 

the contract, so that it could be going on simultaneously with the 
other preparations he is making for having the work commenced. 

The result of this check may not materially aflect either the 
total value of the work or the time within which the work can be 
executed. It may, however, alter the order in which it was originally 
proposed to execute the work and also the disposition of the neces- 
sary plant, and it may be found that the expense of putting down 
these additional bores was fully justified. 

With the information previously obtained when making his 
Tender, supplemented by the additional particulars he himself 
obtains, the Contractor will lay out his works in a manner best 
suited to fulfil the considerations which influenced him in pricing 
his schedule in respect of the depositing of excavations in the 
nearest embankment and other points already referred to* 

He will first direct his attention to those cuttings which take 
the longest time to excavate, or from which he expects to obtain 
building material for use on the work* So that the work may be 
carried on both expeditioudy and economically it may be necessary 
to proceed with cuttings at more than one point simultaneously. 



SERVICE EAILWAYS 

In addition to the ordinary lines of service railway required for 
the removal of the excavations from the cuttings to the embank- 
ments it may be, as already stated, necessary to lay overland 
routes to take the excavations from the euttings* to the embank- 
ments past rock cuttings or the site of viaducts or tunnels under 
construction. If there is not sufficient space within the boundary 
fences for the overland route, additional land will have to be 
temporarily acquired either by the powers of the special Act of 
Parliament under which the works are being constructed, or by 
agreement with the land proprietors. Apart from the possible 
necessity for a service railway or overland route for the rewioval 
of excavations, a line of communication is essential for the con-* 
veyance of constructional materials required for bridges, culverts^ 
etc., along the line, and for general convenience. 

This temporary railway should be laid wiiih a light section 
of rail, generally flat bottomed, and weighing from 40 to 50 Ib* 
per yard, and would be fixed to %ht sleepers The rails shouli 



EXECUTION OF EARTHWORK 4d 

be placed to the gauge of the railway with which the new line will 
connect so that building and other materials can be brought for- 
ward from the existing lines of railway to where they are required 
without the necessity of transhipping them. Generally the sleepers 
of the service railway wiU be laid on the surface of the ground, 
with only the inequalities in the surface removed. Where crossing 
soft or marshy land some additional support may be necessary. 
The gradient should not, as a rule, exceed 1 in 30, and even with 
this steep gradient it will probably be necessary at certain places 
to construct shallow cuttings or embankments* Where any cutting 
or embankment requires to be done it should, if possible, be on the 
line of the permanent railway, thereby saving expense. 

When ravines or steep ground intervene it will either be necessary 
to support the line on a temporary trestle with convenient ap- 
proaches at either end, form a detour to obtain an easier crossing, 
or entirely break the line of communication. 

The service railway will, as a rule, be constructed for a single 
line, but loop lines or passing places will be required at intervals, 
of sufficient lengths to allow of trains used in conveying the excava- 
tions from the cuttings to the embankments or to spoil passing one 
another. These passing places should be situated at such points 
as will cause the least delay to the earthwork operations, and in, 
fixing their position consideration should be given to the con- 
venience for watering locomotives. 



WOKKS 

All works connected with the drainage of the land adjoining both 
the cuttings and embankments, and under the sites of the embank- 
ments, should wherever possible be executed before proceeding with 
the other works, so as to reduce the damage to the earthwork from 
insufficient drainage. Certain of the drainage outfalls may ulti- 
mately be carried alongside the formation of the finished cutting, 
or taken im conduits over the top of cuttings, and it will thus be 
necessary to carry them in temporary channels until such time as 
tike permanent work can be executed. 

The drainage works required are referred to under the heading 
of M Culverts and Djmioage " in Chapter III, and also in 



so EARTHWORK: IN RAILWAY ENGINEERING 



CTTLVEBTS, BBIDGE WALLS, AND RETAINING WALLS 

Where culverts are required under embankments, these should 
be constructed well in advance of the tipping of the materials, 
so that sufficient time may elapse to allow of the masonry becom- 
ing thoroughly hardened, and also that no delay may result 
in forming the earthwork embankments. The same remarks 
apply to the construction of abutment walls of bridges under the 
railway and retaining walls required along the foot of embankments. 
Where line cuttings are supported by retaining walls, the walls 
should be built in trench from the level of the top of the wall. The 
excavations above the level of the top of these walls should be first 
removed, and, after the walls have been built, the excavations in 
front should be taken out. 



SLOPES OP CUTTINGS AND EMBANKMENTS 

The slopes to which the cuttings and embankments should be 
formed will depend on the character of the material. As a general 
rule, cuttings in ordinary soft earth will stand at a slope of 1J 
horizontal to 1 vertical* 

The slope usually adopted for a solid rock cutting is J horizontal 

to 1 vertical, and where soft material 
overlies rock there sliould be a bench 
3 ft. in width between the bottom 
of the slope of the soft jnftt$ml and 
the top of the rock ($4fig. 29). 

These slopes of splfc and rock may 
have to be modified as a result of 
the particulars obtained from bores, 
the amount of water likely to be 
met with, or other information in 

Ite. tt^aafbgWng overlying ^^ ^ ^ ^^ 

In the case of embankments of 

ordinary soft earth the slope of the upper 25 ft, should be 1J 
to 1, between 25 ft, and 40 ft. If to 1, and below 40 ft* 2 to 1* 
This matter is considered in Chapter VI, page 100* 

The exact position of the top of the slopes of cuttings and the 
bottom of the slopea of embankmenta should be accurately marked 




EXECUTION OF EARTEWOKK 51 

out from the cross sections, and where there are any inequalities 
in the surface, additional ground levels should be taken and the 
exact width from the centre line calculated. When the cuttings 
and embankments are being formed the slopes should be brought 
to proper line by means of wooden " batter " rules or " profiles/' 
which may be about 6 or 8 ft. long. In depositing the earthwork 
in embankments, timber cross-heads should be erected at every 
2 or 3 chains, and in fixing the height of them an allowance should 
be made for the subsidence of the embanked material. This 
allowance for ordinary material should be about 1 in. to every 
foot in height, and in making up the embankments the width should 
be proportionately wider. 



SOIL STRIPPING OF SUBffAOE 

After having marked off the lines of the top of the slope of the 
cuttings to be exeavated a and the lines of the bottom of the embank- 
ments known as " lock splitting " of the surface and after the 
centre line and level pegs have been properly transferred, the soil 
and turf over the area to be operated upon should be laid aside for 
the subsequent soiling and turfing of the permanent slopes* 

It is a common practice to deposit this material immediately 
outside of the top of cuttings and the bottom of embankments, and 
between them and the surface catch water ditches where, in the case 
of embankments, it will act as a barrier, forming a temporary toe, 
against which the embanking material will abut when being de- 
posited. 

PROCEDURE IN LINE OXJTTIHGrS 

The simplest form of a railway cutting is where the material to 
be excavated consists of dry sand or gravel and where the depth 
does not exceed 10 ft. In such a case the material would be taken 
out to the full section in one operation. If the cutting exceeds 
10 ft. and is less than 18 or 20 ft., a gullet would first be driven at 
formation level (see Kg. 30). While the guEet is being excavated 
in advance, the wings BB on each side, above the level of 
the top of the wagons, would be removed to the full section 
behind where the eaccavationa are proceeding in the golet, and 
loaded lip simultaneously with the material from the face of the 



52 EARTHWORK IN RAILWAY ENGINEERING 

gullet. After the top level Has been removed tlie wings CO of the 
lower portion would be taken off. In trimming ofi the slopes 
batter rules would be used and the surfaces trimmed from the top 
down. It is usual to cut tracks square to the railway and trimmed 
to the proper batter, these being at intervals of about 66 ft., and 
the surface of the slopes is dressed uniformly between these 
tracks* Where the cuttings are of a less depth than 15 ft. the 
excavations would be removed by hand labour. If the cutting is 
over 20 ft. deep and has of necessity to be removed by hand the 
work would be executed in more than one level. 

As regards the means adopted for disposal of the excavations, 
if the " lead " to embankment or to spoil is less than about 80 
yards ordinary barrows or light hand-carts would be used ; from 




FIG. 30. Excavating cutting 10 to 20 ft. deep. 

60 to 100 yards " dobbin " carts drawn by a horse ; and when 
over that distance and less than about half a mile, wagons of a 
capacity of If cubic yards, running on light rails placed at 3-ffc. 
gauge and drawn by a horse, would be used. When this distance 
is exceeded 4J-yard wagons, and worked by a locomotive with from 
8-irt. to 12-iru diameter cylinder, would be adopted. In the latter 
ease, the gauge of the rails would be the standard railway gauge 
in use. 

The number of wagons taken in a ** rake " would depend 
on the gradient of the service railway, and whether the place of 
deposit is at a higher or lower level than the cutting, but generally, 
with 1 J-yard wagons and horse power a rake would consist of threa 
wagons, and with 4J-yard wagons and locomotive power it would 
consist of from seven to ten wagons* The load should, wherever 
possible, be taken downhill, 

In countries wlwe sharp curves and steep gr&dients are the rule, 
embankments are generally shallow, and any cuttings that exkt 
are of no great depth. In such eases it may be cheaper to obtain 



EXECUTION OF EARTHWORK 53 

embanking material from borrow pits situated alongside the line 
of railway, especially where land is of little or no value. 

When the cuttings exceed 15 or 18 ft, deep and consist of " soft" 
material or loose rock, a steam digger may with advantage be used. 
If the quantity of material in the cutting is more than from 30,000 
to 50,000 cubic yards it will generally be more economical to use 
a digger. With a clean dry sand or soily material there may not 



-y.~*3i).'----j' 

^X oo 



Pia. 31. Width required by steam digger. 

be much saving in cost, but with hard clay, boulder clay, hard- 
bound gravel, shale or loose rock, which are but slowly removed 
by pick and shovel, a considerable saving may be effected, and, 
with all classes of material, the quantity excavated in a given time 
may be two or three times greater when a steam digger is used than 
when the material is removed by hand. 

It is a common practice when the material to be excavated is 
very hard to loosen it by blasting in advance of the cutting face. 



Fia. 32. Leaving wings on gullet. 

The charges would be placed about 20 ft. in advance of the face of 
the cutting and about the same distance apart and would be sunk 
to about 12 or 15 ft. below the surface. Care should be taken to 
see that the charges are at least 3 ft. from the formation slope of 
the finished cutting, so that the slope may not be damaged. In 
boulder clay, loose rock, or similar material, the explosive used 
would be black powder, instead of dynamite or nifero-glycerine, 
as would be the case if the material to be aranoved wore solid rock, 
the object being merely to lift the roek ofi its natural bed or 
up the boulder clay so that it may be the more 
by tibe e$eam digger. 



M EARTHWORK; IN RAILWAY ENGINEERING 

The cutting of a single line of railway with a width of 17 or 
19 ft. at formation level is too narrow to allow of a steam digger 
being used, and it will be necessary to keep the level at which the 
steam digger is operated about 3 or 4 ft. above formation, as shown 
in Fig. 31. 

When the width is unrestricted, as in the excavations for a depot 
or series of sidings, a larger and heavier machine than would work 
in an ordinary railway cutting may with advantage be used. It 
is thus that in large canal undertakings considerable quantities of 
excavations can be removed in a much shorter time and conse- 
quently at a less cost than can be done in ordinary railway work* 

In the removal of the excavations of a railway cutting long 
gullets should not be driven in advance of the main excavations 





. 33. Cutting into slope. 

(see Kg. 32), as otherwise the weight of the projecting pieces may 
draw or strain the material outwith the intended slope of the 
cutting. The sides of the cutting should be battered back as the 
work proceeds, the slopes being always entirely completed within 
at least 100 ft. of the working face. 

A very objectionable practice is to cut away the toe of the slope 
when the excavations are being removed by a steam digger (see 
Fig. 33), and thereafter to throw down the upper portion of the 
wings to replace the part cut away. As a consequence a slip may 
result through water finding its way into the back of the material 
that has been thrown down. If the toe of a slope is so cut away 
it should be made good by stone filling as referred to in Chapter VI, 
page 112. 

DISPOSAL OF EXCAVATED MATEBIAIi 

In order to obtain the best results from a cutting it is necessary 
that the means of disposal be most complete, wMle at the same 
time a great deal depends on the management of the operations to 
ensure that the work is skilfully executed* The usual mode of 



EXECUTION OF EARTHWORK 



55 



cedure in excavating a soft cutting and tipping an embankment 
where a steam digger is employed is as follows. 

Service rails to the standard gauge in use would be laid from 
the cutting face to the tip ends at the embankment. A light 
locomotive engine would work at the tip end, while a horse or 
light locomotive would be employed at the cutting face, ajid a 
heavier locomotive than that used at the tip end would run between 
the cutting and the embankment. If the " lead ** to embankment 
is over two miles, more than one locomotive would be necessary 
for running the earthwork trains, and passing places would also 
be required at convenient intervals, probably every two miles. 





Jili|iliWtLUUlmu^ 

Plan 




Section 

FIG, 34. Arrangement in cutting three Hues of railway. 

The general arrangement at the cutting face where there is 
sufficient width is shown in Fig, 34. 

A short distance back from the face a passing place or loop line 
is provided for leaving empty wagons and taking away full wagons. 
At the cutting face the service railway branches into three lines, 
the steam digger being placed at the end of the centre road. The 
train of empty wagons, in which there would be eight or ten wagons, 
would be placed in the centre road behind the digger. An empty 
wagon would be run by a horse through the " jump " or sharp 
tera-out and placed at the end of each of the two side roads, so 
as to be in line with the front of the digger. When each wagon has 
i iBed it fe propelled! or dbawn out into the portion of the side 



56 EARTHWORK IN RAILWAY ENGINEERING 

road behind the " jump " and replaced by another empty wagon. 
When the whole rake has been filled the next train of empties will 
be due to arrive and these will be left in the loop while the loco- 
motive engine, which has brought them forward, pulls out the full 
wagons, and having pushed the train of empties into the centre 
road behind the digger, the engine takes the full train away to 
embankment. 

With the two side roads there is no delay with the digging opera- 
tions, as, when a full wagon is being replaced by an empty wagon 
on one road the digger is filling a wagon on the other road, To 
be able to get three roads it is necessary that the formation width 
be not less than 28 or 30 ft., so that in a single line cutting 



\behtod Digger 




* 35, Arrangement in catting two lines of railway. 

operations require to be carried out at a level of about 4 ft, above 
formation level to get that width. 

If the work is conducted at formation level in a single line cutting, 
which would be about 17 or 19 ft. wide 3 it is necessary to have the 
digger placed in advance of the wagon to be filled (see Fig. 55). 
In this case there would be only two roads. Empty wagons would 
be placed in the loop, and after each is brought forward and filled 
it is placed in the straight road from which th whole rake is lifted 
and taken to embankment. 

A steam digger can work well in a cutting from 18 to 22 ft* deep. 
In deep cuttings the work would be carried on at different levels 
of 20 to 25 ft. between each. When the depth of a cutting is slightly 
more than the bucket can reach the material is pushed into the 
cutting by crowbars or is brought down by the operating of t&e 
bucket. 

The arrangement at the embaaJanent end is shown at Fig, S6. 
Full wagons from the cutting axe run into the line A* The 
which have just been emptied are standing on the liBe B, and 



EXECUTION OF EARTHWORK 57 

the engine which lias brought forward the full wagons has been 
uncoupled, it runs the empties back to the cutting. The light 
engine for tipping is standing in the line B. The first of the 
full wagons is set in motion by a pinch-bar and run down the 
line 0. 

The most favourable conditions for depositing material in 
embankment are obtained when the lines of railway are falling 
towards the tip end. In high embankments the gradient can be 
steepened and the upper or narrow portion subsequently made up. 

On the diagram the gradient down to the tip end is shown to be 
easy so far as the point X, but beyond that point it is much steeper, 
but not more than, say, 1 in 30. 

When the full wagon is within 3 or 4 yards of the tip, the front, 
which is hinged on the lower edge, is opened by having the fastening 

Cattfnff 




. 36* -Arrangement at embankment end, 



at the side thrown up by a man striking it with a shovel. The 
end of the service road is elevated by having a few sleepers raised 
above the level of the end rail, and when the front wheels of 
the wagon strike against this buffer the body of it is thrown up 
and the muck tipped out. 

Meantime the tipping engine has got in behind the empty wagon 
and immediately thereafter the second full wagon is run through 
the crossing into the line D and emptied alongside o the first. 
The engine with the empty wagon from the line C m taken out and 
run into thie line D, and the second empty wagon, having been 
attached, both empties are taken out and placed behind the full 
wagon at poiat A* The whole " rake " having been emptied in 
this way they are placed in the line B to allow of another rake 
being run into tibe line A, following on which the enipty wagons 
ai!e nm back to the cuttwg. 

When* on. account of the shaHownest of the anborjkmerit or when 
the top portion of a h%b emlmnfcpaent the material 



58 



EARTHWORK IN RAILWAY ENGINEERING 



has to be deposited on a rising gradient, it will be necessary for the 
stunting engine to propel the full wagons right up to the tip end. 
The position and number of the passing places already referred 
to will be fixed by the time which is occupied in filling the wagons 
at the cutting or emptying them at the embankment. 



BISKS OF BELAY 



When the excavated material is dry no difficulty is experienced 
in tipping it, but if water is present in the cutting which cannot 
be kept separate from the excavations, progress is retarded. If 
the excavated material is gravel the water will probably have 




&7. Method of expediting emptying wagons. 



drained itself off before the embankment is reached ; but if it 
should consist of clay or muddy sand, the material will most 
likely have been converted into a thick paste, closely adhering to 
the sides and bottom of the wagon by the time that the muck train 
has reached the tip end- This adhesion of the material to the 
wagons may be reduced by spreading a layer of clean gravel or 
engine ashes in the bottom of the wagons. 

For the purpose of expediting the work at the tip end, when bad 
material is met with the following method has been successfully 
adopted (see Fig. 37). One end of a chain was fixed between the 
sleepers on the inclined road and after having been carried under- 
neath several sleepers the other end was attached to the wagon 
which, was being tipped before it had reached the i&cline. The 
tip engine, having given the wagon an extra hard push, the wagon 
was sent down the incline, and on being held up fey the 



EXECUTION OF EARTHWOBK 59 

of tlie chain it was brought to a sudden stop at the tip end and 
the muck thrown out. 

When the material is bad there may be considerable loss of 
time in removing it from the wagons, and also by reason of 
derailments, or wagons going over the end of the embankment, 
in which case the wagons cannot be emptied quick enough to keep 
the steam navvy constantly employed ; but, when conditions are 
favourable for disposing of the material, the reverse is generally 
the case, and the supply of excavated material may have to be 
augmented by having a squad of men working by hand labour 
filling wagons at some other part of the cutting. In removal of 
excavations there is always a portion of the slope which cannot 
be reached by the steam digger, and it is usual to fill so many 
wagons of each rake in trimming ofi the slope in the portion of the 
cutting behind where the digger is working. 

In wet weather there is also a great risk of delay by reason of 
engines and wagons being derailed on the service railway. If 
the material should be of a clayey description, which with water 
is converted into a slurry composition, a quantity of it will 
drop on the way to embankment, and it is thus very important 
that the line of communication should receive proper attention 
so as to avoid derailments. The further the embankment or place 
of deposit is from the cutting the greater is the necessity for 
keeping the service railway in good condition. 



PBOCEDUBE ADOPTED IN FOBMING EMBANKMENTS 

If the embankment is over 20 ft. in height it should be brought 
up in layers, these being, in the case of high embankments, from 
15 to 20 ft. thick. When the width at the tip end is less than 30 ft. 
two wagon roads would be used in the manner already described ; 
but when the width is greater than 30 ft. additional roads are 
necessary, an extra road being laid for every additional 15 ft. in 
width* 

When there are three or more lines at the tip end, on of the 
eeuto lines would b used for holding the empty wagons after 
the BJaterial had been tipped in the side roads. The centre roads 
WQtild be carried forward simultaneously with, but a little in the 
rear of those at the side. In forming an embankment the two 



58 



EARTHWORK IN RAILWAY ENGINEERING 



has to be deposited on a rising gradient, it will be necessary for the 
shunting engine to propel the full wagons right up to the tip end. 
The position and number of the passing places already referred 
to will be fixed by the time which is occupied in filling the wagons 
at the cutting or emptying them at the embankment. 



BISKS OF DELAY 



When the excavated material is dry no difficulty is experienced 
in tipping it, but if water is present in the cutting which cannot 
be kept separate from the excavations, progress is retarded. If 
the excavated material is gravel the water will probably have 




FIG. 37. Method of expediting emptying wagons. 



drained itself ofi before the embankment is reached ; but if it 
should consist of clay or muddy sand, the material will most 
likely have been converted into a thick paste, closely adhering to 
the sides and bottom of the wagon by the time that the muck train 
has reached the tip end. This adhesion of the material to the 
wagons may be reduced by spreading a layer of clean gravel or 
engine ashes in the bottom of the wagons. 

For the purpose of expediting the work at the tip end, wten bad 
material is met with the following method has been successfully 
adopted (see Fig. 37)* One end of a chain was fixed between the 
sleepers on the inclined road and after having been carried under- 
neath several sleepers the other end was attaehed to the wagoai 
which was being tipped before it had reached the incline. The 
tip engine, having given the wagon an extra ha^d puah> the wagon 
was sent down the incline, and on being heJd tip fey the tightening 



EXECUTION OF EAETHWOEK 59 

of the chain it was brought to a sudden stop at the tip end and 
the muck thrown out. 

When the material is bad there may be considerable loss of 
time in removing it from the wagons, and also by reason of 
derailments, or wagons going over the end of the embankment, 
in which case the wagons cannot be emptied quick enough to keep 
the steam navvy constantly employed ; but, when conditions are 
favourable for disposing of the material, the reverse is generally 
the case, and the supply of excavated material may have to be 
augmented by having a squad of men working by hand labour 
filling wagons at some other part of the cutting. In removal of 
excavations there is always a portion of the slope which cannot 
be reached by the steam digger, and it is usual to fill so many 
wagons of each rake in trimming off the slope in the portion of the 
cutting behind where the digger is working. 

In wet weather there is also a great risk of delay by reason of 
engines and wagons being derailed on the service railway. If 
the material should be of a clayey description, which with water 
is converted into a slurry composition, a quantity of it will 
drop on the way to embankment, and it is thus very important 
that the line of communication should receive proper attention 
so as to avoid derailments- The further the embankment or place 
of deposit is from the cutting the greater is the necessity for 
keeping the service railway in good condition. 



PBOCEDUBE ADOPTED IN FORMING EMBANKMENTS 

If the embankment is over 20 ft. in height it should be brought 
up in layers, these being, in the case of Mgh embankments, from 
15 to 20 ft. thick* When the width at the tip end is less than 30 ft* 
two wagon roads would be used in the manner already described ; 
but when the width is greater than 30 ft. additional roads are 
necessary, an extra road being laid for every additional 15 ft. in 
width. 

When there are three or more lines at the tip end, one of the 
centre lines would be used for holding the empty wagons after 
the material had been tipped in the side roads* The centre roads 
woold be carried forward simultaneously with, but a little in the 
imr of those at the side. In forming an embankment the two 



62 EABTHWORK IN BAILWAY ENGINEERING 



CUTTING IN BOCK 

The method adopted for the removal of rock from the excava- 
tions will largely depend on the character of the rock, and whether 
it is proposed to use it for building or other purposes on the contract, 
or merely to run it to spoil embankment. 

In the event of the removal of the rock being the primary con- 
sideration the material would be taken out regardless of its value, 
the object being to remove the maximum quantity at the minimum 
cost. Blasting, if allowed, would then be carried on continuously, 
and if there is a greater uniform depth than from 12 to 14 ft. opera- 
tions would be carried out at more than one level (see Fig. 38), 



Surface Tff 




FIG. 38. Excavating rock. 

It will generally be found more convenient to take off one Hft con- 
tinuously for some distance before proceeding with the removal 
of the rock immediately underneath, but the mode of procedure 
will largely depend on the means for disposal of the excavated 
material. The blast holes would be of a depth of about 6 ft, and 
placed at about 16 ft. apart, but no hole should be closer than 3 ft. 
to the finished batter of the cutting, so as to ensure immunity from 
damage to the rock outwith the finished slope. Three men would 
be engaged at each bore hole, if the drilling is done by hand, while 
other ten or twelve men would be engaged loading up the excavated 
material* 

The material after being loaded into skips would be lifted 
and emptied into wagons either by steam cranes placed on the top 



EXECUTION OF EARTHWORK 63 

of the cutting or by travelling cranes working on tie line of railway 
at formation. As a preventive against stones flying out of the 
cutting the blast hole should be covered over and weighted down, 
A good cover consists of pieces of trees 6 in. in diameter and 6 ft, 
long tied together by chains- If blasting is prohibited by reason of 
the proximity of property, public highways or adjoining railways, 
the materials would be taken out by pinch-bars. This matter is 
further referred to in Chapter V, page 78, 

If the removal of the rock from the cutting is not the key to the 
completion of the work, it would be taken out in large masses in a 
manner somewhat similar to that usually adopted in quarrying 
operations. In the case of freestone, limestone, or other stratified 
deposit the rock would be shifted by splitting it with wedges or 
by what is known as the " plug and feather J? method, and by 
raising it ofE its natural bed by means of crowbars. Small charges of 
gunpowder would be used to shake large posts of rock without 
shattering it. 

Where granite is met with in large quantities blasting will be 
regularly carried on, and the larger masses which are brought down 
will be subsequently split up into smaller pieces in a similar manner 
to the softer stratified rock. 

For the removal of the rock so quarried the blocks of stone which 
are to be used for building or other purposes will be run out into 
a depot set apart for the purpose, while the smaller material or 
debris would be put into tip wagons and run to spoil embankment, 
or it may be used to advantage for pitching slopes exposed to 
water, making up roads, or broken up for concrete, or crushed for 
use as sand, or other purposes. 

When rock is met with in station dep6ts, where there may be 
platform fronts to be formed in the rock, a track would be cut either 
by shearing the rock by hand labour or by means of a channelling 
machine. This would be done previous to the removal of the centre 
portion, and there would thus be no risk of damage to the sides 
of the finished cutting. 

BXAMELBS OF KAILWAY CUTTINGS 

The following examples from actual practice illustrate the 
manner usually adopted in the removal of excavations from rail- 
way cuttings* 



64 EARTHWORK IN RAILWAY ENGINEERING 

Each of the examples is for a single line of railway where the 
operations are carried on in a confined width and consequently 
require more consideration than where there is greater freedom for 
work. 

(1) Kg. 39 is a profile of a railway cutting for a single line of 
railway, the greatest depth of which was 46 ft. and the quantity 
of material to be excavated was 80,000 cubic yards. The material 
consisted of sand and gravel for a depth of 6 ft. under the surface, 
underlying which there was clay until within 10 ft. of formation, 
while the bottom 10 ft. consisted of " faikey " fireclay. The line 
embankment which was situated at the upper end of the grade 
required about 60,000 cubic yards of material, and the balance 
of 20,000 cubic yards had to be deposited in a spoil bank at the 

Spotl Bank J^^^^ f ' Mff ":^^^><^ 

alongside Railway* '$//////& 3^^^^^^'^ 

A^0^^^Qaa/jtrty of Material in Cutting 8QJDQQ Cub. Ycfs 
R^^^ Gradient / In 40 

' I Fur ' 7/57 

FIG, 39, Example of railway cutting (1). 

lower end of the cutting. The portion of the cutting shown hatched 
at the lower end was excavated by hand labour, and run to spoil, 
and a short length at the upper end, sufficient to allow of a steam 
digger being erected, was also removed by hand. 

The digger was wrought through the upper portion of the cutting 
oix a rising gradient taking off the left-hand half of the excavations, 
following on which it was run back to the point of commencement 
taking ofi the right-hand half. It was then run along the service 
railway to the point A and let down a steep slope to the point B. 
The triangular portion A, B, C was then taken out, it being necessary 
to carry on operations at a level of about 5 ft. above formation, in 
order to get a width of 30 ft. which was necessary for operating the 
" Ruston " digger which was used. Thereafter the digger was again 
run through the cutting from the lower end, working this time at 
formation level. The "faikey" fireclay of the lower 5 ft. was 
blasted out in front of the digger and lifted by the digger bucket 
into wagons placed behind the poi&t where the blasting operations 
were proceeding, the digger in this operation being used merely aa 



EXECUTION OF EARTHWORK 65 

a crane. The whole of the work in each, of these operations was 
carried out on rising gradients, thus allowing of any water that 
was met with in the working face having a free outfall. 

(2) The cutting of which Fig. 40 is a profile had a maximum 
depth of 37 ft., of which the bottom 11 ft, consisted of solid rock, 
while the quantity of material to be excavated was 130,000 cubic 
yards. The material on the top of the solid rock consisted of 
boulder clay in certain places, while at other places loose rock was 
met with* Operations were commenced at the lower end of the 
cutting by hand labour until a depth of face of 8 ft. was obtained, 
when a digger was erected and taken through the cutting on the 
top of the solid rock, the excavated material being run to embank- 
ment at the lower end of the gradient* Blasting was resorted to in 
front of the digger for the purpose of loosening the soft rock and 
boulder clay. After the material on the top of the solid rock had 
been removed the excavation of the solid rock was proceeded with 
by hand labour, operations being carried on both at the lower end 
and at the centre of the cutting, in both cases working up the 
gradient of the railway. The material from the lower end was run 
down grade to the embankment, while that from the upper end was 
taken to embankment up the grade. The excavated rock was 
lifted into wagons by means of steam cranes placed on the top of 
the slopes of the cutting. Water was met with in the upper part 
of the cutting, and this had to be drained oft by shearing a track 
through the rock to the working face at the lower end of the 
cutting. 

(3) In the case of Fig. 41, which was also for a single line of 
railway, the cutting was 43 ft. deep, while the tdtal quantity of 
material to be excavated was 245,000 cubic yards. The cutting had a 
length of 67 J chains (1485 lin. yds.), and consisted of fine sand with 
a large volume of subsoil water for a length of about 18 chains at 
the upper end, hard boulder clay, which was perfectly dry, for a 
length of about 19 chains (418 En. yds.), hard clay with water coming 
tkrougii open fissures caused by mineral worfrings, for about 16J 
ctaipis (363 lin. yds,), and hard clay without water for the remain- 
ing distance of 14 chains (308 lin. yds.)* 

The excavated material had to be run to embankment 
f som the top end of the cutting. The fine sand at the upper 
6EMl was e$avated by hand labour on a riismg gradient, which 



66 



EARTHWORK IN RAILWAY ENGINEERING 



I 





EXECUTION OF EAETHWORK 67 

had just sufficient fall to allow of the water draining itself 
off. In the removal of the sand, side and cross ditches were 
cut so as to have the material when put into wagons as dry as 
possible. A steam digger was set to work at the point B, and took 
off one half of the cutting so far as the point C, from which point 
the digger could reach the full section of the cutting as far as the 
point X. The excavated material was run back through the sand 
cutting to the embankment. In excavating the portion of the 
cutting through the wet clay on a falling gradient it was necessary 
to have a steam pump, which was erected on a carriage placed 
immediately behind the digger, for the purpose of raising water from 
a sump placed at the working face from which the water was 
pumped into a drain laid at the top of the cutting. The remainder 
of the cutting was removed by a heavy digger, working at a level 
of 5 ft. above formation and the lower portion was subsequently 
removed by means of a lighter digger working at formation. The 
means adopted to support the slopes of this cutting through the 
wet sand are referred to in Chapter VI, page 115. 



CROSSING BOG- OR MOSS LAND 

The surface of a bog consists of peat, coarse grass, heather, etc., 
and is of a very porous description. If the skin of the bog is un- 
broken it has a considerable bearing capacity, and if it can be 
drained the bearing capacity is very largely increased. 

If drainage of the surface can be effected no great difficulty will 
be experienced in taking a railway across it ; but if, on the other 
hand, natural drainage of the surface is impossible the construction 
of the railway may only be executed with difficulty and at great 
expense, and the subsequent maintenance will also be a costly 
item. The ideal railway across a bog is where the railway is either 
laid on the surface or on a shallow bank and where the bog has a 
imtaral drainage The bog land will be of very little value and ample 
width should be acquired to make the drainage as perfect as possible. 

B%* 42 shows a section of railway crossing bog land. Ditches 
i ffe. wide by 4 ft. deep were cut on dither side of the railway 40 ft. 
distant from tik centre line aad cross ditches 3 ft* wide and 4 ft* 
, to 3 ft. deep were cut from the longitudinal ditches to within 18 ft. 
'fan* th* centre line and 33 ft, apart. P&rfc of the turf removed 



68 



EARTHWOEK IN RAILWAY ENGINEERING 




from the ditches was used for levelling up any 
inequalities in the surface of the ground on 
which the railway was to be constructed, the 
object being to strengthen the natural surface 
of the ground. Brushwood and branches of 
trees were afterwards laid on the surface for a 
width of 10 ft. on each side of the centre line 
and to a depth of 2 ft. 6 in. depending on the 
springy character of the ground, the lower 
half being laid with the branches in line of the 
railway, and the upper half laid crosswise to 
the line of the railway. The brushwood was 
covered over with mountain till or clay, which 
generally underlies the peat and is found along 
the edges of the bog. On the top of the clay 
the permanent way of the railway was laid. 

The ballasting of the permanent way con- 
sisted of ashes or gravel as the slag or broken 
granite or whinstone generally used cuts 
through the clay covering the brushwood. 
With a view to more uniformly distributing 
the load on to the brushwood covering, the 
sleepers of the permanent way were placed 
closer together than usual, leaving only 
sufficient space for the proper packing up of 
the sleepers. 

If further drainage is thought? to be necessary 
than above referred to, an additional longi- 
tudinal ditch could be cut on each side of the 
railway, in which case the cross ditches con- 
necting the two longitudinal drains may be 
placed further apart. In the event of aay 
banking material requiring to be deposited OB 
the top of the brushwood care should be taken 
to ensure that the weight of the banking is 
placed evenly on each side of the centre line 
simultaneously, otherwise the unequal loading 
will tend to break tkcotigh the surface of 
the bog. 



EXECUTION OF EARTHWORK 



69 



It is desirable that the ditches for the drainage of moss land 
should be cut nine or twelve months previous to the laying of the 
permanent way, and it is also well that the laying of the brushwood 
should not be commenced until after a spell of dry weather. 

On account of the levels of the railway it may be necessary to 
have part of the line when entering bog land in cutting, and if the 
bog is very soft it may be necessary to deposit embanking material 
down to the solid ground underneath. No clayey material should 
be used for this purpose on account of the water of the bog 
converting it into slurry. The best material for the purpose 
consists of the excavations from a rock cutting. If the railway 
should be in cutting through bog land and the peat is of a somewhat 
firm description, it may be found sufficient to replace a depth of 




of Bog 



Fia. 43. Section of railway approaching bog. 

2 or 3 ft. of the peat by clay closely compacted, on the top 
of which brushwood and trees should be placed as in the manner 
already described. 

For the drainage of the railway in a bog cutting deep ditches 
should be formed along the bottom of the slope on each side. 

Kg. 43 shows a section of railway approaching a bog. The 
bog was contained on all sides and there was no natural drainage. 
Before entering the bog land a sand cutting 55 ft. deep had to be 
cut through, and in forming this cutting a drainage outlet for the 
bog was obtained, otherwise the line across the bog would have 
been much more difficult to construct. 

Where the bog caaxnot be effectively drained the various works 
of levelling the inequalities in the surface, tke laying of brushwood, 
awd the subsequent daying over of the brushwood should receive 
Bp0<mal attention, TM$ may not prove effective, and it may 
be necessary to fill up the bog along the line of railway with 



70 EARTHWOEK IN RAILWAY ENGINEERING 

embanking material. The subsequent maintenance of a railway 
across bog land may be very expensive by reason of breaks taking 
place in the surface and the necessity for depositing material in 
order to get a solid foundation. 



WIDENING- OF EXISTING- BAILWAYS 

In executing the widening of an existing railway the first con- 
sideration must be the safety and the regular working of the traffic 
on the railway generally. Trains will no doubt be so frequent that 
possession of the railway can only be obtained during the night 
or on Sundays, and any operations during the day will require 
to be executed entirely clear of the running line. 




PIG. 44. Widening of railway -single to double line. 





Fia. 45. Widening of railway two lines to four lines, 

The widening work should be fenced off from the existing rail- 
way and any crane or steam digger should be so clamped or con- 
trolled that in swinging round it shall have a clear distance of 
6 ft. from the nearest rail of the running line. 

If the widening is of a single to a double line the total width of 
the formation of the railway will be increased 11 ft. (see Fig. 44), 
while if the widening is from double line to four lines the formation 
width will be increased 17 ft. on each side (see Fig. 45), 

It will thus be seen that in the case of the doubling of the single 
line there will not be clearance for a digger to be employed, and the 
excavations will, therefore, require to be removed by hand labour. 

In the case of widening from two to four lines the operations 
will not be so restricted and a steam digger can be used if desired* 

If the material in the soft cuttings will stand at a steep slope for 



EXECUTION OF EARTHWORK Tl 

a time, it will generally be found convenient to run a gullet through. 
the cuttings at formation level, so that the materials can be taken 
from both ends of the cutting to the same embankment, and it 
will also allow of the material in the slopes or stone from rock 
cuttings being removed simultaneously with the excavations at 
the ends of the cuttings. 

The operations should be proceeded with at as many points as 
possible along the route of the widening, attention being more 
particularly paid to the cuttings from which there is the largest 
quantity of material to be removed, and to the removal of stone 
in rock cuttings. 

It may be necessary to take part of the excavations to an embank- 
ment separated from the cutting by a bridge or viaduct which 
requires to be widened, or to a spoil bank situated away 
from the widening work, and it will be an advantage to excavate 
the material at intermediate points, as above referred to, fining the 
material into wagons placed on the Main Line during the night or 
on Sundays. 

It may also be possible to arrange for trains of excavations to be 
run over the existing railway from cuttings to embankments 
situated at a distance or to a spoil bank between traffic during the 
daytime. Storage sidings for full and empty wagons shall, 
therefore, require to be provided at the widening work, and there 
should be no shunting operations on the existing railway. 

Any temporary connection with the existing lines should be under 
the control of the nearest signal box, and when the excavations are 
being removed from the cuttings into wagons placed on the running 
lines a flagman should be stationed at each end of the operations 
to warn the men of the approach of trains. 

The traffic on the running lines should be conducted by the 
Railway Company's engines, and the men and the wagons for the 
removal of the excavations should ako be supplied by the Company. 

It will generally be found that the most suitable wagons for the 
removal of the excavations are those with sides about 3 ft. high and 
with folding down doors extending the whole length of the wagon. 

Care should be taken to see that the wagons are not so fully 
loaded as to cause the material to spill over on the ballast of the 
running line. 

Aft *h J* ^ QP* tb$ onfltfiig line wbw tike material is being 



72 EARTHWORK IN RAILWAY ENGINEERING 

loaded into wagons the ballast should be kept clean by covering 
with old sleepers or sacks. 

In rock cuttings where the material is of commercial value 
quarrying operations can be proceeded with during the daytime, 
and the stone can be loaded into wagons placed on the existing line 
at night or on Sundays- 

If the soft excavations are of too hard a description or if rock 
is to be removed, blasting can be resorted to, but as there may be 
only one or two occasions during the day when there is a long 
enough interval between the passing of trains, a number of charges 
should be fired at one time. The firing of the charges should only 
be done after permission has been given by the look-out man who 
has previously arranged the matter with the signalman in the 
nearest signal box. 



EARTHWORK CONSTRUCTED BY COOLIE OR BLACK LABOUR 

In countries where coolie qr black labour has to be dealt with, 
the cost of labour is so low that it would be entirely out of the 
question to employ costly plant to execute the work, 

It is usual to sublet the work in sections or lengths of two or three 
chains, and both men and women assist at the work. A large number 
of hands are employed, and the construction of the cuttings and 
embankments is carried out very speedily. The natives fill their 
baskets with pick and hoe, and carry them on their heads, except 
in the case of long loads, when donkeys with baskets or gunney 
bag panniers may be used. 

In some countries light wagons running on a railway of about 
2-ft. gauge and pushed by hand are used for conveying the material 
a distance. Cuttings and banks are formed independent of one 
another, but instead of depositing the excavations from the 
cuttings into the embankments they are taken to spoil alongside 
the railway and the material for the banks is obtained by excava- 
tions from borrow pits, except in the case of the pa^fc of the 
cuttings which immediately adjoin the banks, where it is more 
economical to put the material into the embankments rather 
than take it to spoil, While this method of procedure entails the 
handling of a much greater quantity of material than would be the 
case if the practice of making up the embankment from the line 



EXECUTION OF EAETHWOEK 73 

cutting were followed, it is considered the best arrangement in 
view of the system of letting out the work which is adopted. 

For the making up of shallow banks and the lower portion of 
high banks, the material from the borrow pits is simply piled on 
the bank, and in high banks the borrow pits immediately adjoin 
the end of the bank. The banks should be carried up in layers 
of two or three feet for the full width and over the whole length, 
and in depositing the material, the natives should be made to walk 
over what had previously been deposited so as to have the banks 
as compact as possible. By the constant walking to and fro a very 
solid and satisfactory bank is obtained. In executing the work 
in this manner there is no delay such as is experienced where 
wagons are used, and where there may be interruptions by reason 
of them not being timeously forwarded. In excavating rock hand 
boring tools are generally used, these being considered more 
economical than machine drills, owing to the supervision which is 
required for the latter. 



SPECIAL METHODS ADOPTED IN FOKMIN& BAILWAY 

EMBANKMENTS 

In countries where there may be long stretches of level or prairie 
land, or where the ground may be comparatively uniform in level, 
and where there may not be sufficient depth or quantity of material 
to be excavated to warrant the use of heavy plant, scraper machines 
are largely used. 

The earth is loosened by having the surface ploughed over, and 
after the surface has been broken up, the material is taken, to 
embankment by a drag scraper, where the lead may be from 100 
to 200 ft. For longer leads a wheel scraper is used, as it is more 
economical. 

In crossing long stretches of level ground the railway will in all 
probability be on a low embankment so as to obtain through 
drainage and immunity from so^drifts, and if the embanking 
material is to be obtained from the ground alongside the railway, 
it can conveniently be deposited by means of a grader working 
along the foot of the slope and casting up the material as it goes 
along. The embanking material so deposited will be very loose* 
and it will be well to have the upper 2 or 3 ft. made up fey depositing 



74 EARTHWORK IN RAILWAY ENGINEERING 

the material with drag or wheel scraper for the purpose of consolidat- 
ing it. 

These machines are referred to under Chapter V, dealing with 
Contractor's plant. 

In the construction of railways in countries where there is plenty 
of timber and where the obtaining of sufficient embanking material 
may involve considerable delay in bringing the railway into opera- 
tion, timber trestle structures have been erected to cross deep 
ravines. These have been placed not with a view to being perma- 
nent, but to suit the purpose for the time being, it being intended 
to subsequently replace them by earthen embankments. The 
execution of this work can be proceeded with at a time when it is 
most convenient, and does not necessarily incur any serious inter- 
ruption of the regular traffic working of the railway. 

In delaying the filling of the embankments an opportunity is 
given to the Engineer to ascertain what size of culverts should be 
provided at crossing of streams. 

HYDRAULIC METHOB 

A large amount of this work of filling in trestles has been done 
in America, and the method of carrying out the work of placing 
the material in embankment by hydraulic means would, under 
certain conditions, appear to have its advantages. 

Not infrequently slips of considerable extent have taken place 
shortly after the opening of a line for traffic, and the material 
which it is necessary to remove can be conveniently disposed of by 
filling in trestles at a cost not exceeding that of running it to spoil. 
If, however, the material requires to be specially excavated and 
land can be obtained free or at little cost, the hydraulic system 
commends itself. It has also the advantage that there is no delay 
by reason of muck wagons blocking the traffic on the railway. 
For the success of this method it is a necessity that there should 
be an abundant supply of water with sufficient pressure to operate 
the plant. Under ordinary circumstances it would not be economi- 
cal to erect power stations for the purpose of obtaining the necessaay 
pressure. 

The operations consist essentially of the washing out of the 
material from the side cutting or borrow pits by meaM of a Jet f 
water under high pressure^ and the conveying of it to the 



EXECUTION OF EARTHWORK 75 

to be embanked by means of wooden troughs or flumes wMch are 
raised or slued as may be necessary as tlie work proceeds. In the 
building up of the embankment various means are adopted to dam 
back the slurry. 

On the Northern Pacific Railway a method successfully adopted 
was to deposit alternate layers of earth and straw. The earth was* 
spaded out from the inside, and on the top of it was laid a bed 
of straw, this being compacted by another layer of earth. The 
embankment was carried up in this manner until within a few feet 
of the surface of the railway, and the upper layer was afterwards 
formed with material deposited from wagons in the usual way. 
The deposited material became remarkably solid in a very short 
time and the embankment was entirely free from subsidence. 



EXAMPLE OF EXCEPTIONALLY HEAVY EARTHWOKK 

The execution of exceptionally heavy earthwork on a line of 
railway in New Jersey is worthy of attention. 1 

The line has been formed across country with the object of 
reducing the distance and also improving the curves and gradients 
which previously existed on a former line of railway. 

By the former route the length between the points of termination 
was 40 miles, while by the new line the distance was reduced to 
28J miles. On the former line the maximum curve was 6 54' 
(831 ft. radius) , and the maximum gradient was 1-14 per cent (1 
in 87*7), as against 3 30' (1637 ft. radius), and 0-55 per cent (1 in 
181-8) respectively by the new line. 

The excavations and embankments are of exceptional magnitude, 
there being 7,315,000 cubic yards of excavations and 14,621,000 
cubic yards of embankment. There 13 thus an excess of 7,306,000 
cubic yards of embankment which had to be obtained from side 
cutting or by the bulking of the rock when put into embank- 
ment. 

One of the embankments extended in length to three miles and 
had a height of from 75 ft. to 110 ft,, the quantity of material 
required to fill it being 6,625,000 cubic yards. 

The high banks were brought up in lifts of 30 ft., timber trestle 
bridges being largely used for the purpose of tipping the material. 

1 Engineering Mecord, 17th April, 



T6 EARTHWORK IN RAILWAY ENGINEERING 

In forming some of the large embankments cable-ways were 
adopted. In one instance a cable-way had two spans of 1000 ft. 
and 1200 ft., with three wooden towers 60 ft., 150 ft., and 135 ft. 
high respectively. The working of the cable-way is described as 
follows : 

<e It is essentially a suspension bridge, carrying a cage or platform 
on which a 3-ft. track is laid. The cage is so made that it can be 
moved forward along the main cable as fast as the embankment 
is built. The cars are pushed to the very edge of the fill and dumped 
and then pushed out on the cage, which is of sufficient length to 
hold eight cars, or a gross load of 48,000 Ib. As the fill progresses 
the suspended track is shifted along the cables by placing clamps 
12 ft. apart in advance of the previous ones and hanging from them 
a suspender rope with an adjustable tackle, to which a needle beam 
is fastened to carry the new stringers and the additional track. 
On account of the sag in the cables the lengths of these suspenders 
and other tackle are made adjustable." 

It is claimed by this method that there is greater ease of working 
when the excavation consists of rock or large boulders which might 
seriously damage a timber structure. 

The borrow pits from which the extra embanking was obtained 
were situated above the level of the banks, and in some instances 
the loaded tip wagons were allowed to gravitate to the bank, being 
kept in check by having one end of a cable, which passed round 
a drum, attached to them, the other end being connected to the 
railway wagons which were drawn back to the pit for refilling. 



CHAPTER V 
PLANT USED IN EXECUTING EAKTHWORK 

AN: axiom in manufacture by machine tools, which is equally 
applicable in the execution of earthwork, whether by hand or 
machine labour, is that the system or machine which accomplishes 
a given result quickest, best, and at the same time at the least cost, 
is the one to be selected. 

REMOVAL OF EXCAVATIONS BY HAND LABOUR 

Soft excavations. The shovel is the tool in general use for the 
removal of soft excavations by hand labour. The iron blade of the 
shovel is of a hollow or scoop shape, and is usually sharp pointed. 
Where the material to be removed is of a wet or muddy description, 
the shovel would be broad pointed, and the sides turned up so as 
to better contain the material. 

Except in the case of loose earth, or when the material is easily 
removed, a pick would be used in conjunction with the shovel to 
loosen it. 

Where the material is of a tenacious, clayey description and free 
from stones, it may be dug out by a sharp-pointed shovel with a 
thick upper rim, similar to what is on an ordinary broad-pointed 
spade, and would be used in a similar manner. 

It is very desirable that the shovel, spade, or pick should be of 
as light a character as possible, consistent with the rough usage to 
which it is subjected, in order that the energy expended in handling 
the tool may be reduced to a minimum. 

Rock excavations. In excavating shaly or loose rock, or rock 
wMch can be removed from its natural bed without blasting, a pick 
is used. The point of the pick is driven into the joints or clefts 
of the rock, and, by using the curved back of the pick as a fulcrum 
and putting back the end of the shaft, a considerable pressure ca& 
be brought to bear on the point in removing the rocfe. 

77 



78 



EARTHWORK IN RAILWAY ENGINEERING 



A pick for removing rock has generally a broad or chisel-shaped 
point at one end and rounded point at the other end- By having 
a broad point there is more of a knife edge, while at the same 
time equal strength, and this allows of the point of the pick being 
inserted into a closer joint than a blunt rounded point would enter. 
The pick in use for the removal of soft material is rounded at both 
ends. 

A crowbar chisel-pointed at one end and round-pointed at the 
other end, similarly to the pick, is used, where greater pressure is 
required than can be obtained with a pick. For the purpose of 
getting a leverage a piece of wood, stone, or other hard material 
at hand is placed under the bar so as to act as a fulcrum when 
prising up the rock, and by inserting wedges in the open joint the 
bar can be released or tilted up to allow of the fulcram bain 
shifted closer to the joint, thereby getting into a better position to 
further raise the rock from its bed. Where a large block of rock ife 
being lifted from its bed two or more crowbars may be used simul- 
taneously. 

Where the rock is of a close or solid description a groove is formed 
in it with a pick, along the Hne on which it is to be split, and iron 

wedges are driven at intervals by blows 
from a sledge hammer. The wedges are 
placed at about a foot apart and the blows 
applied on every alternate wedge when 
passing over them in one direction, driving 
the intermediate wedges when coming back 
over them. The rock is, of course, more 
easily split along its natural bed than at 
right angles to the bed. 

If the pieces of rock so loosened from 
their beds are too large to lift by hand or 
by the crane power which is available, they 
are broken by means of a sledge hamiaer or 
split by wedges, or by " plug and feather." 
The latter method is, as a rule, only adopted 
when the rook is to be used for bttEcfeg 
purposes, in wMch case care is neeema^y 
to ensure that the blocks ce i^gular in 
shape. 




Fe set hers 



E leva b ion. 




Plan. 



. 46. Excavating rock 
by "plug and flatter. " 



PLANT USED IN EXECUTING EARTHWORK 79 

The " plug and feather ** (see Fig. 46) consists of a wedge-shaped 
piece of steel, or plug, which is driven between two segmental- 
shaped pieces of wrought iron or feathers. The holes in which the 
feathers are placed are drilled by a chisel or small hand drill. The 
plugs are driven in between the feathers alternately as in the case 
of wedges until the rock splits along the line of the holes. 



REMOVAL OF EXCAVATIONS BY MECHANICAL MEANS 

Soft excavations. The expediency of removing earthwork by 
mechanical means has already been referred to. Various machines 
are in use for the removal of soft excavation, but for ordinary rail- 
way work the principal one is the steam digger or shovel. 

The primary requirement in a steam shovel is to have a machine 
that will withstand a large amount of rough usage, and conse- 
quently the working parts must be made of the toughest material. 
In this connection cast steel is largely used. The design of the 
machine must also allow of a certain " play " or freedom of action 
which will take up the jolting or hammering without the parts 
which must of necessity be close fitting being unnecessarily strained. 

The various movements of a steam digger are very similar to 
the movements of a man when excavating earth by hand labour. 
The hand shovel is first lowered, then pressed into the ground, and 
when filled it is raised, swung round and emptied into a barrow or 
wagon. 

In the case of the steam digger the bucket is first lowered into 
the bottom of the cutting by releasing the lifting rope. It is then 
pulled up, being at the same time pressed into the cutting, and 
when filled, it is swung round and the excavations emptied into a 
wagon. 

RtTSTON STEAM CBANE NAVVY 

The Huston steam crane navvy is the digger in general use in 
Great Britain, and is typical of the best class of this jxiacMo^. 

In the earlier typ of Btaston digger* the boiler and lifting gear 
wwe fixed to the carriage in a similar manner to what is don 
in the Rtt&ton steam shovel* Jpiereafter referred to, and could 
cply revolve through about 180 degrees ; but in the Ruston 



80 EARTHWORK IN RAILWAY ENGINEERING 

navvy or digger now in use the machine revolves through, a com- 
plete circle, thereby allowing of wagons being loaded immediately 
in the rear of the machine. 

There are several sizes of Ruston steam navvies, but the machine 
most suitable for general railway excavation work is what is known 
as the No. 12 machine (see Pig. 47). 

The nett weight of this machine is 41 tons, and it will work 
in a cutting 27 ft. deep without breaking down the top by hand. 
On account of the long reach of the jib, the digger is able from one 
position to excavate to a width of 42 ft. at the bottom of the cut 
to 63 ft. at the top. This range of working allows of the excavated 
material being loaded into wagons with, less shunting and also of 
the bucket being brought more directly over the wagons, thereby 
reducing the labour in cleaning up material that may have dropped 
over the sides of the wagons. The door of the bucket when open 
will clear a height of 19 ft. above the level at which the digger is 
placed and where the cutting does not exceed 10 ft. deep, or where 
the cutting is in side-lying ground with the low side not more than 
10 ft. deep, the excavations can be loaded into wagons placed on 
a line of rails outwith the cutting, which may be a considerable 
advantage in the removal of the excavations to embankment or 
to spoil. 

It is not proposed to enter into the mechanical details of con- 
struction of the machine, but the following details should be noted. 

The boiler is of the vertical cross tube type, and the water previous 
to entering it is heated in a water heater by exhaust steam, this 
resulting in a considerable saving of fuel. 

The jib is constructed of steel plates and heavy angles, and 
the bucket arm which consists of two oak beams, one on 
each side of the jib, is heavily reinforced by mild steel plates so 
as to withstand the heavy stresses to which it is subjected. 

The stroke of the bucket arm is controlled by toothed gear fixed 
to the jib, which engages with long steel racks fixed to the under- 
side of the bucket arm, the toothed gear being operated by engines 
mounted on the jib* 

The bucket is heavily constructed of steel plates and angles and' 
fitted with a steel casting to receive the bucket arm. The teetfa, 
of which there are four, are carried about the full depth of the 
bucket and consist of mild steel shaiiks with renewable manganese 



PLAtfT USED IN EXECUTING EAH r PHW6RK 8l 




BLB.B. O- 



82 EARTHWORK IN RAILWAY ENGINEERING 

steel points fitted on a renewable lip plate. The teeth, are fitted to 
the bucket plates with counter-sunk bolts, which allow of them 
being quickly renewed. 

The hoisting rope is double and the drum, which is of a large 
diameter, has right- and left-hand grooves on it, so as to increase 
the life of the rope and also equalize the pressure upon the drum 
bearings and side frames. 

The carriage of the digger is supported on two axles with wheels 
to suit both the ordinary gauge of 4 ft. 8| in. and a gauge of 9 ft. 6 in., 
the narrow gauge being provided for the purpose of travelling the 
digger from one section of the railway to another, while the broad 
gauge wheels, which are provided with double flanges, are used 
when the digger is in operation, thereby giving the machine a 
broader working base. 

In carrying out the work, when the bucket is lowered to the 
bottom of the cut it is allowed to swing a little past the vertical, 
and in doing so the catch of the door drops automatically into its 
place. The bucket is then pulled up the face of the cutting, being 
kept hard pressed into the cutting by the racking engine. After 
it has reached the top of the cut, or if it is filled before it reaches 
that height, it is pulled a little back from the cutting face and slued 
round until it is over the muck wagons, and, when in proper position, 
the door of the bucket is released by the man at the jib pulling a 
cord which is attached to a link connected with the catch of the 
door. 

The bucket generally used with No. 12 machine has a capacity 
of 2 cubic yards, which represents about If cubic yards of solid 
excavation. 

For heavy railway excavation work with large quantities of 
material to remove, the Ruston No. 20 machine is well adapted. 

The nett weight of this machine is 55 tons, and it will work 
in a cutting 29 ft. deep without breaking down the top by hand. 
The digger, from one position, will excavate to a width of 44 ft. 
at the bottom of the cut to 72 ft. at the top. The bucket generally 
used with this machine has a capacity of 2f cubic yards, represent- 
ing about 2J cubic yards of solid excavation. 

To allow sufficient space to operate these machines it is necessary 
that the cutting should be not less than 30 ft. wide at the bottom, 
so that in a single line cutting it is necessary that the level at which 



PLANT USED IN EXECUTING EARTHWORK 83 

tie digger is operated should be about 3 or 4 ft. above formation 
level of the railway. 

As already stated, tlie output from a cutting which, is being 
excavated by means of a steam digger is largely controlled by the 
facilities which exist for having the excavations removed, but with 
a constant and uninterrupted supply of wagons for taking away the 
material and with operations carried out under favourable con- 
ditions the No. 12 Ruston navvy has excavated 350 cubic yards 
of boulder clay and 800 to 1000 cubic yards of sand in a working 
day of ten hours ; while the No. 20 machine has excavated 550 




FIG. 48. Ruston steam crane navvy. 

cubic yards in well blasted rock, and 1200 to 1400 cubic yards in 
a chalk cutting during the same time. These figures would, of 
course, require to be reduced to make allowance for bad weather 
or other delays* 

The relative output of the two sizes of machine referred to may 
be said to be proportionate to the pressure of the teeth of the 
bucket on the" cutting face, which in the case of the No. 12 machine 
is 12 tons, and in the case of the No. 20 machine 20 tons, and the 
capacity of the lifting bucket is arranged accordingly. 

By removing the bucket and bucket arm, the navvy can be 
used as an ordinary steam crane, the lifting power of the cranes 
beiiig 12 tons and 20 tons respectively. 



84 EARTHWORK IN RAILWAY ENGINEERING 

The illustration (Fig. 48) shows the usefulness of the long racking 
gear. It will be observed that five wagons were loaded from one 
position of the digger. 



WILSON STEAM CKANE NAVVY 

The Wilson steam crane navvy, illustrated at Fig. 49, is also 
largely used in Great Britain for the removal of earthwork. 
So far as actual working results are concerned, the 12-ton Wilson 




Wilson steam crane navvy. 



navvy is very similar to the No. 12 Huston navvy already referred 
to 3 and is an equally serviceable machine. 

Instead of the long bucket arm in the Buston digger the Wilson 
digger has a " luffing " jib, thereby lengthening the reach of the 
bucket, 

The special feature of this digger is the steam racking cylinder 
which operates the bucket arm. The cylinder is bolted to the arm 
and the arm is pivoted to the underside of the jib and radiates 
therefrom. The bucket is fed up to its work by means of the 
racking cylinder, and can be moved in or out a distance of 2 ft. 
as desired, 

The jib can be adjusted from a minimum radius of 16 ft. to a 
maximum radius of 25 ft. The machine weighs in working order 
43 tons. 



PLANT USED IN EXECUTING EAKTHWORK 



85 



Some of the machines of this type are provided with a bent 
jib (see Fig. 50), the advantage of which is that it allows wagons 
to be brought closer to the machine, thereby reducing the labour 
in bringing forward the wagons. 

This digger can conveniently work in a width of 25 ft. at forma- 
tion level, and will reach to a width of 50 ft. 

The bucket used for average material has a capacity of 2J cubic 




Pio, 50. Wilson steam crane navvy (with bent jib)* 

yards, and can excavate a cutting 18 ft. deep without breaking 
down the top by hand. 

When used as a crane this steam navvy will lift a load of 12 ton? 
at a radius of 16 ft. 

EtJSTON STBABtf SHOVEL 

The Euston steam shovel, illustrated at Fig. 51, is specially 
made for dealing with heavy earthwork in large quantities, and 
where the operations are not confined to the limits of an ordinary 
railway cutting. 

The nett weight of this machine is 78 tons, and it will excavate 
& cutting 27 ft. deep with a maximum cutting radius of 32 ft. 

The bucket has a capacity of 3| cubic yards. 



86 EARTHWORK IN RAILWAY ENGINEERING 

- 9 . 9Z _ 




J-y 

' "S 



1 
I 



P3 



PLANT USED IN EXECUTING EARTHWORK 87 

The larger output consequent on the more powerful description 
of the machine commend it for specially heavy work. 



LUBEOKER LAND DBED&EB 

This digger machine has been extensively used in connection 
with canal excavations and also to a limited extent in railway work 
where a large quantity of soft material has to be removed. 

The machine is built on the same principle as a marine dredger 
(see Fig. 52), the excavations being removed by a series of buckets 
attached to two endless chains. The machine is of two types, 
to cut out the excavations either above or below the rail level on 
which, it travels. 

It works on rails running parallel to the direction of the cutting, 
advancing automatically on the rails as the work progresses, i.e. 
as the chain of buckets projecting at the side excavates the soil and 
throws it into trucks for transportation. The trucks stand behind 
the excavator and at the rame level on which the machine is placed. 

In order that the chain of buckets may be kept constantly in 
use it is necessary that the rails on which the machine travels 
should be shifted forward from behind the machine, this being done 
after the machine has made one or several cuttings, and, so as not 
to disturb the operations, there should be a length of railway equal 
to from three to five times that of the train of wagons which is being 
Med. 

To prevent the sand or earth from falling between the trucks 
the machine is provided with movable chutes, which may be 
turned round so as to direct the material from one truck into the 
next and prevent it falling on to the track. 



BOOK EXCAVATIONS 

Where rock is removed by blasting, the drill holes into which the 
explosive agent is inserted may either be driven by hand or by 
machine drills. SpeaMng generally, the harder the material and 
the more difficult to drill by hapd t the greater is the advantage of 
machine drilling. 

In open cuttings of railways there is generally a much larger 
proportion of soft material than rock, for the reason already stated 



88 EARTHWORK IN RAILWAY ENGINEERING 





9 

TJ 

M 



i 



PLANT USED IN EXECUTING EARTHWORK 89 

that the route can be chosen so as to avoid the more costly rock 
excavations, consequently in general railway work the rock will 
be in many cases removed by hand drilling* 

HAND DBILLINQ 

The bar used in drilling by hand is generally 6 or 7 ft. long and 
about 1 J in. in diameter, the point being chisel-shaped and about 
1 in. wider than the body of the rod, so as to leave space for lifting 
and lowering without any jamming of the hole. The hole is some- 
times driven by " jumping " it, that is, by raising and dropping the 
rod about 1 ft. 6 in. or 2 ft. at a time, two men being engaged in so 
doing. After each blow the bar is turned slightly round in the 
hole so as to ensure that the chisel edge will strike on a new 
surface. Water is poured into the hole to keep the point of 
the tool cool and also to soften the rock. The rock is ground into 
dust or small chips, and the water " cakes " it, thus making it more 
easy to remove when cleaning out the hole. It is necessary that 
the hole be cleaned out frequently, as otherwise the broken material 
will retard the drilling operations, and this is done by means of a 
spoon-shaped scraper attached to the end of a thick wire. 

The rate of progress of drilling rock by hand amounts to from 
12 in:, to 15 in. per hour, working in sandstone, limestone, or material 
of a like nature ; but in whinstone or igneous rock the rate will not 
exceed 6 in. to 8 in. per hour. 



MACHINE 

There are two distinct types of machine drills, percussion drills 
and rotary drills . In the former, the action may be said to be similar 
to that which exists in hand drilling, the hole being formed by 
repeated blows of a tool> but much more rapid than in hand drilling* 
In the rotary drill, the hole is formed by the tool drilling out the 
rock in a similar manner to the working of an auger in drilling wood. 

The essential features of a good drill are that it should be of 
light description and easy to moyg from one place to another, 
simple in construction, avoiding complicated parts, thereby making 
it more easily mastered by the men at hand, compact, so that 
ii? ean be used in restricted or oo&fined situations, of perfect 



90 



EARTHWORK IN RAILWAY ENGINEERING 



workmanship, and consisting of materials specially suited for the 
particularly heavy work to which it is subjected. 

Various types of percussion drills are made, but an example of 
Ingersoll-Rand Company's drill may be taken as typical of this 
class of machinery (see Fig. 53), 

In this drill, the rod, head, and chuck are all in one piece, whereas 
if they had been constructed in separate pieces, there would have 




5& Ingersoll-Rand rock drill. 



been a great tendency for the parts to become loose with the shock 
of 400 to 600 blows applied per minute. 

In the best drills no cast iron is used, there being steel castings, 
tooled steel, malleable iron, drop forgings, and special metal wheie 
suited. The drilling tools are made of the best grade tooled steel 
fco cope with the very severe work to which they are put, 

In the cylinder of the machine there is no cushion pressture to 
retard the stroke and diminish the blow, and the blow is tims 



PLANT USED IN EXECUTING EARTHWORK 91 

absolutely " dead." The drill has a wide variation of stroke, which 
is secured by simply " cranMng " the machine forward* This 
has great advantage when driving a hole on an oblique surface, 
and also admits of the hole being quickly started. The rotation 
of the rod is effected by having spirally grooved rod or rifled recesses 
in the back of the piston. 

For the purpose of lengthening the bore as the work proceeds 
each tool has a set of drills* A fresh tool is put on the end of the 
piston rod as every few feet of depth are driven, and this allows of 
the drill just removed being handed over to the blacksmith for 
dressing. 

Different types of drilling bits are in use for the various classes 
of rock to be cut through. In sandstone, a flat blunt bit gives the 
best result, while in an extremely hard rock, the X form gives 
the best results. In rock of an irregular texture, and where it is 
too hard for the flat bit, an X-shaped end is considered most 
suitable, as the probability of rifling or grooving the hole is more 
remote. 

The best results in mechanical drills are secured with live active 
air in preference to steam, but the particular situation and the 
facilities obtainable will determine the method adopted* The 
working parts are somewhat different in the air and steam operated 
machines. 

Where steam is used a considerable loss of power results if it is 
necessary to have long lines of piping. In general, steam is probably 
the most convenient and economical system, on account of the 
expense in providing compressed air plant. In recent years elec- 
tricity has been introduced to operate the compressed air plant, 
and this is advantageous where long lengths of piping may be 
objectionable. 

Rotary drills have not found favour on public works, and they 
are only mentioned here on account of the success which attended 
the driving of the Simplon TunneL The machine which was used 
there was worked by hydraulic power, the inventor and maker 
being Mr. A. Brandt. 

Hand hammer drills operated by compressed air have lately 
been used (see Fig. 54). This machine was first used as a simple 
naeans of drilling shallow blast holes in boulders too ladrge for 
removal by a steam digger or too heavy to be handled at a stone 



92 EARTHWORK IN RAILWAY ENGINEERING 

crasher ; but as no tripod or stand is necessary and as the hand 
hammer drill is easily handled and moved about, and can be 
operated in confined places where the tripod machine could not be 
worked, it is now extensively used. The cutting tools are either 
hollow, solid, or spiral-shaped. In hard solid rock where the 
drills cut freely the hollow tool is used, and by passing the exhaust 
air down the tube the debris at the foot of the holes is blown away 




Jto. 54. Hand hammer drill. 



from the cutting edge. In soft rock, a spiral steel is uspd, the spiral 
acting as a conveyor for bringing the cuttings to the surface. 
Solid cutting tools would be used for driving " tip-holes " where 
the broken rock in the hole would fall out. 

The time occupied in drilling operations varies considerably with 
different classes of material In granite the speed of drilling may 
be about 2 ft. per hour, whereas the speed in sandstone or limestone 
rock may be from 6 to 8 ft* per hour. 



PLANT USED IN EXECUTING EARTHWORK 93 



BLASTING 

The explosive agent used in blasting is determined by tlie charac- 
ter of the material to be dislodged, and whether it is proposed to 
make use of it for building purposes. 

If no use is to be made of the rock for building and the material 
is being removed without any regard to the size or shape of the 
blocks, a high-grade explosive would be used if the rock should be 
of a tough description, such as whinstone or granite ; but if the 
material should be a sandstone or a limestone rock, and where 
there is less resistance, a less virulent explosive would be more 
effective. If the material should be boulder clay, as in the case 
of breaking down a stifi cutting to feed a steam digger, the least 
virulent explosive is used, namely, black blasting gunpowder, or a 
low-grade granular nitro-glycerine. To get the best results, the 
percussive force of the explosive should be proportionate to the 
resistance of the material being removed. 

If the rock has a commercial value and care has to be exercised 
in its removal, small charges of gunpowder would be used, the object 
being only to " shake " the rock and lift it from its bed* 

In firing the charge, if there are only a few shot-holes, a powder 
fuse would be used ; but if blasting is carried on extensively the 
charges would be fired by an electric exploder. Reference is made 
to the removal of rock in railway cuttings in Chapter IV, page 62. 



CONVEYANCE OF EXCAVATIONS FROM CUTTINGS TO 
EMBANKMENTS 

The oldest and simplest method of taking earth in small quantities 
short distances is by means of a wheelbarrow. The barrow in 
general use is made of wood and has a capacity of about 4 cubic feet* 
Barrows may be conveniently used where the distance to be carried 
is less tiban about 150 ft., and to facilitate operations^ planks of 
timber, or barrow tracks, are laid down on which to travel. 

Whealbacrows are also made of iroa, but tJie wooden barrow 
is generally used on account of being more conveniently repaired. 

"Where excavations have to be taken for some distance over firm 
gcottod, or alor^g formed roads, horse carts are used. With fairly 
good roads, a horse can drag a cart up an incline of 1 in 10 for 



94 EARTHWORK IN RAILWAY ENGINEERING 

short distances, and on a longer regular grade of about 1 in 12. 
In the cart in general use, the shafts are in one piece with the body 
of the cart, and to unload it the horse is detached from the shafts. 
Carts for removing excavations are sometimes made with the 
shafts and body in separate portions, thereby enabling the exca- 
vated material to be emptied without detaching the horse from the 
shafts. 

The capacity of an ordinary cart is about 24 cubic feet. 



TIP WAGONS 

For taking excavations short distances, iron tip wagons, running 
on a narrow-gauge railway, are sometimes used. These are of 
various designs, but a very convenient type is that illustrated by 





Iron tip wagon. 



Fig. 55. The usual size of this tip wagon has a capacity of 1 cubic 
yard, and travels on light rails placed 2 ft. 6 in. apart. The under- 
frame of the car is in a separate piece from the body and has vertical 
frame supports at each end, on the sloping sides of which are jaws 
which engage two pins fixed on each end of the box. The pins are 
about 10 in. apart, and the box is held in position during transit 
by means of a catch pin which locks the box with the carriage ; and 
while there is no possibility of overturning during transit, very 
little effort is required to tilt the box over and unload it. 

It win be observed from Fig, 55 (6) that when the box is turned 
over the sloping side is in such a position as to aEow the material 
to fall out without the assistance of any spade work. The wagon, 



PLANT USED IN EXECUTING EAETHWORK 95 




96 EARTHWORK IN RAILWAY ENGINEERING 

when empty, is easily propelled along a level or up a flat 
gradient by a man pushing it, and when full, a horse can 
haul three or four wagons at a time along a level or up a 
slightly rising gradient. This type of wagon is largely used in 
countries where black or coolie labour is employed and where all 
the work is done by manual labour. 

Several types of iron box tip wagons of somewhat similar con- 
struction to that above referred to are in use and are equally 
serviceable. 

For ordinary railway work, flat-bottomed wagons are generally 
used. These are constructed both in wood and in iron, and are 
of varying capacities (see Fig, 56). 

Where the " lead " to embankment does not exceed half a mile 
and where the material is being excavated by hand, 1-yard wagons 
running on a 3 ft. gauge railway are used. A rake of three loaded 
wagons can be drawn by a horse up an easy gradient. If a light 
engine is used for hauling the wagons more can be taken at one 
time, and gradients, if they are of no great length, as steep as 1 in 
30 can be negotiated. 

If the distance to be hauled exceeds half a mile, or if a steaik 
digger is in use, larger wagons of, say, 4 cubic yards capacity, 
running on the standard railway gauge, may be used, and the&e aro 
hauled by a locomotive. Wagons can be had with either side tip 
or end tip action. The question of side tip as against end tip 
wagons is referred to in Chapter IV, page 60. 

Where excavated material has to be taken over existing lines of 
railway in removing it from the cutting to embankment, it will be 
conveyed in wagons provided with springs and buffers similar to 
the rolling stock of the railway on which they have to travel 



I>BAa AND WHEEL SCRAPERS 

A method largely used in America for removing excavations 
from railway cuttings in open country is by means of drag and 
wheel scrapers. 

The object of these machines is to remove the material from tihe 
place of excavation, drag or wheel it to and tip it at the place of 
embankment. 

Previous to the material being conveyed from the cutting to 



PLANT USED IN EXECUTING EARTHWORK 97 

embankment the surface of the ground is, unless the material is 
of a very loose description, broken up by a plough.. In ordinary 
earth, the plough is hauled by two horses and two men are employed, 
a driver and a ploughman. If the material is of a hard description, 
the plough is weighted. 



DRAG SCRAPER 

For short leads of from 100 to 200 ft. a drag scraper is used. 
The drag scraper, or " slusher " as it is sometimes called, consists 
of a scoop-shaped iron box with a cutting edge, the capacity of it 
being about 5 cubic feet. 

Fixed near the front and to either side of the box by a 
pivoted connection is a bent rod which forms an attachment 
for a team of horses to drag the scraper over the ground, while at 
the back there are handles to guide it when it is being filled and 
emptied. 

When it is desired to fill the box it is tilted up slightly by raising 
the handles when being dragged along the ground. The sharp 
edge cuts into the ground and the earth is scooped into the box. 
On the handles being released the box takes up its original position, 
and the box of earth is hauled to the tip. To empty it the driver 
again lifts the handles and with the sharp edge cutting into the 
ground the box is suddenly pulled up, which causes it to turn on 
the pivots at the connection of the drag link, with the result that 
the earth is thrown out. 

A team of horses is required to haul the scraper, and the driver 
usually empties it, other men being employed for the filling opera- 
tion and also for the levelling of the ground at the tip. Where the 
material is of a light description the driver of the team may also do 
the filling^ 

WHEEL SCRAPER 

Where the lead exceeds 200 ft. the wheel scraper, or *' wheeler/' 
is used. The principle of it is the same as the drag scraper, but 
toeing a larger box it is carried on wheels. By means of a lever 
attachment the box can be tilted up to be filled or lowered as re- 
quired. The average capacity of the box is about one-half cubic 

B.BJL H 



$8 EARTHWORK IN RAILWAY ENGINEERING 

yard. The wheel scraper is drawn by two horses, although it is 
usual to employ another team, known as a snatch team, to assist in 
filling the box. Where ordinary soil is being removed, it is usual 
to employ one man extra to the driver, but in heavy soil it is 
customary to employ two extra men for the purpose of filling. 



CHAPTER VI 

SLIPS IN EARTHWORK AND THE MEANS TAKEN 
TO PREVENT THEM 

THE importance of being fully informed as to the character of the 
materials likely to be met with in executing earthwork, and the 
necessity for thorough drainage works being provided have already 
been referred to, but the bearing of these matters on the ultimate 
success of the undertaking will be better appreciated when ques- 
tions relating to slips have been considered. 

CHARACTERISTICS OF VARIOUS MATERIALS 

Slips in earthwork are due to the resistance between the particles 
or between plane surfaces in contact having been overcome. The 
tendency of all materials is to take up a horizontal position, and 
the fact that one material will stand at a steeper slope than another 
is due to that material having a greater frictional or cohesive 
resistance. The slope at which a material will stand relative to 
the horizontal is termed the angle of repose of that material. 

Clean dry sand or gravel is supported by the frictional resistance 
between the particles or stones, while, on the other hand, clay is 
almost entirely supported by the cohesion of the mass. 

A moderate amount of moisture or water helps to support earth- 
work, but if there should be an excess of water the resistance to 
movement is very considerably reduced. With a fine dry sand there 
is no cohesion between the grains when in a perfectly dry state, 
but with the presence of moisture or dampness cohesion is estab- 
lished which enables the sand to stand at a steeper slope than it 
would otherwise do. If there is an excess of wetness the sand will 
]Q,ot stand except at a very flat slope. The larger the particles or the 
coaper the sand the steeper will be the slope at which the sand 

trill stand. 

99 



100 EARTHWORK IN RAILWAY ENGINEERING 

In tike case of clay, the presence of moisture very largely assists 
the stability, but an excess of water will dissolve the clay and 
destroy the supporting power. Pure clays are dangerous on account 
of their stability being so much reduced by water. Certain clays 
are so hard that they require a pick to excavate them, but after 
continuous exposure to wet weather they get so soft that they 
will only stand at a very flat slope. 

The stability of a soil thus depends on the effectiveness of the 
means taken to protect the material from or to remove any super- 
fluous and consequently dangerous water. At the same time it 
must be kept in view that all clayey soils require a limited quantity 
of moisture for their stability, and that by exposure to the atmo- 
sphere the moisture may get dried out and the supporting power 
of the clay become reduced in consequence. The expansion of 
clay when wet and the contraction in dry weather are also respon- 
sible for considerable damage to earthwork. 

The following are given as the slopes at which earthwork will 
stand under ordinary conditions : 

Gravel . . . . 1 horizontal to I vertical. 

Dry sand . 1J 1 

Compact earth. . . . If I 

Clay, well drained . 1J 1 

Clay, wet , . 3 to 5 1 

In a rock cutting the slopes will range from J to 1 to 1 to 1, 
depending on the character of the material. Certain material, 
such aa faikes or fireclay, may be very difficult to ^move from a 
cutting, but after weathering may require to be trtemed ofi to a 
slope of If to 1. 

The above figures should only be used as a guide, and in deter- 
mining what slope the material will take regard must be had to 
the actual conditions prevailing and the experience obtained under 
similar circumstances, in view of the fact that the stability is so 
much affected by atmospheric conditions and slight changes in 
the character or composition of the material. 

The character of the materials in the cuttings and the slopes 
which it will be necessary to adopt as well as of the material to be 
put into embankment should receive full consideration by the 
Engineer as otherwise serious trouble may afterwards result* The 



SLIPS IN EARTHWORK 101 

possibility of flatter slopes being required than would at first sight 
appear necessary should be fully considered before the construction 
of the works is proceeded with. 



SLIPS IN CUTTINGS 

Slips in cuttings are either due to the action of water flowing 
off the surface of the adjoining lands, water in the strata cut through, 
to rainstorms or water in the form of moisture in the atmosphere, 
or they may be due to the taking away of the natural support by 
the removal of material which was necessary to maintain a state of 
equilibrium. 

As regards slips caused directly by the action of water, the 




^Intercepting 

, . drain 

dram 

FIG. 57* Drain for intercepting field 
drains and surface water. 

resulting damage may consist of the loosening and gradual crum- 
feHng away of the surface of the slope and the falling in of the portion 
^tx>ve for want of proper support. The water may have come 
OIL to the slope on account of the surface or agricultural drainage 
of title land not having been properly intercepted, or it may have 
percolated througji the strata. As already stated, the necessary 
drainage of the adjoining lands should be executed prior to the 
exoa^tioias in lie cutting being proceeded with. 

For the purpose of intercepting surface water it is usual to have 
an open ditch cut on the high side of a cutting immediately outside 
of the railway fence (see Fig. 57). If there are any agricultural 
drains which would be interfered with in forming the railway cutting 
these should be intercepted by laying a drain immediately outside 
of the railway fence, which would either discharge into a pipe laid 
down the slope of the cutting and connected with the drainage 
of the f ormatibn of the railway, or be led entirely clear of the railway. 
It is usmt in layiog this drain to leave the track which has 



102 EAETHWOEK IN RAILWAY ENGINEERING 

cut for it unfilled for the upper 9 inches, thereby forming a ditch 
to catch the surface water. Agricultural drains will probably be 
about 2 ft. or 2 ft. 6 in. below the surface, and the intercepting pipe 
would be a 6-in. or 9-in. fireclay pipe with open joints, the joints being 
surrounded by broken stones which would be carried up the trench 
to within 9 inches of the surface. The agricultural drains would 
be led into this main drain either by branches on the main drain or 
by forming an opening in the upper surface of the pipe. If the 
material in which the drains are laid is of a clayey description it 
would be well to form the lower half of the joints of the intercepting 
pipe with cement, so as to have a watertight channel, and thereby 
prevent water finding its way into the slope of the cutting. 

There is a danger of water from the surface of the adjoining land 
which flows into an open ditch finding its way into the substrata, 
and thereby causing damage to the slopes of the cutting. It is thus 
necessary that consideration be given to the character of the 
material in which any ditch or surface catch-water drain is being 
formed, and if any danger is feared it is better that the surface 
water should be allowed to flow freely down the slope of the cutting 
into the formation drains. Where open ditches are formed they 
should be periodically inspected and cleaned out, so that no damage 
may result from obstruction. 

If the water is coming through the strata it may have been 
impossible to have known of its existence or to have made any 
provision for its removal prior to the cutting being excavated, 
but as soon as it is observed when the cutting is in progress 
no time should be lost in dealing with it. The source of water 
appearing in the cutting should be immediately investigated, and, 
if it cannot be traced and intercepted either at its source or at 
some distance from the cutting, the water should be conducted 
clear of the excavation operations. In the event of water appearing 
on the slope in small quantities or at a few isolated points, it may 
only be necessary to lay rough stone pitching over small areas 
and lead drains therefrom down to formation of the road or railway 
cutting. An important point to observe is that when a drain is 
laid to carry away water which may collect in stone pitching or in 
dry filling it should be placed in the bottom of such pitching or dry 
filling, and thus prevent damage by water collecting at a lower 
level. 



SLIPS IN EARTHWOKK 103 

Not infrequently springs are tapped in forming a cutting, and 
these may be effectively dealt witli by inserting a pipe in tlie slope 
and leading the water to the surface, or if this is not sufficient, the 
source of it may be traced by digging a trench and conducting the 
water safely clear of the slope. No attempt should be made to dam 
back or check the flow, or retard the free discharge of water appear- 
ing in a cutting, as otherwise it is certain to break out at some other 
point in a much more aggressive manner. 

As a general rule the water would either be intercepted by laying 
a drain at the level of the porous strata outside of and well clear 
of the top of the slope of the cutting, or it would be allowed to come 
to the face of the slope and be conducted by means of drains down 
to formation level of the railway. To intercept the water before it 
reached the slope might, unless the bottom level of the stratum 
which contains the water is near the surface, prove to be very costly, 
but if properly carried out it will be the more effective method, and, 
keeping in view the future maintenance of the work, it will probably 
prove the more economical in the end. 

Where maintenance work of the description of keeping slope 
drains in order is required, the subsequent remedial work to main- 
tain them in a satisfactory state of repair is frequently delayed or 
overlooked and indifferently executed, and it is thus better that 
as little water as possible be allowed to percolate through to the 
surface of the slope. 

The water appearing in the strata may be traced to a natural de- 
flection of the surface of the ground, and situated some distance from 
the top of the slope, or the outcrop of the water-bearing stratum may 
be ascertained from the inclination or " dip " as seen from the level of 
the two sides of the cutting, and in either case, it may be much less 
costly to lay a pipe to drain the natural hollow or intercept the water 
in the stratum by a much shallower drain at some distance from 
the cutting, than would be necessary if the drain were formed 
immediately behind the top of the slope. 

The following example will illustrate the manner in which work 
of this description has been carried out. In taking out the exca- 
vations of a railway goods yard, which was about 25 ft. deep, a 
considerable volume of subsoil water was met with a few feet 
below the surface of the ground. The material in the cutting 
was of a fine sandy description with a proportion of clay mixed 



104 EARTHWORK IN RAILWAY ENGINEERING 

with it, and as long as it was dry or contained only a small quantity 
of water it was quite good for embankment purposes, but with the 
large volume of water that was met with in the lower part of the 
cutting it was rendered altogether unsuitable. 

The material was being taken to an embankment about three 
miles distant, and, on account of the water in the cutting, the 
excavated material was converted into slurry, and the service 
roads were very expensive to maintain in proper order by reason 
of the drippings from the wagons, and the cost of tipping the 
excavations at the embankment was also excessive. It was thus 
necessary that the water should either be intercepted before it 
reached the cutting face or that the material with the water in it 
should be run to spoil embankment. 

All the excavations from the line and station cuttings were 
required for the purpose of making up the embankments, and, 
if the material in question had not been available, side cutting 
would have been necessary, and this would have entailed at least 
double the cost iif removal. It was therefore decided to intercept 
the water before it got to the cutting, and this was done by laying 
a drain below the level of the formation of the yard. In executing 
the work it was necessary to close-timber the sides of the trench and 
lay each pipe and form the joints under the constant inrush of water 
and silty sand. AH field drains cut through in laying the main drain 
were connected to the main drain and the pipe was led to a proper 
outfall. The joints of the pipes in the main drain were thoroughly 
packed round by stones, and the trench up to the level of the water 
in the stratum was also filled with broken stones. The result was 
entirely satisfactory and the excavations were removed and de- 
posited in embankment without farther trouble. 

In work of this description the most convenient drainage outlet 
may be by a drain or several drains led down the slope of the 
cutting which would discharge into a pipe laid along the formation 
of the railway. 

When the water in the stratum is allowed to come to the surface 
of the slope (see Fig. 58) a complete system of drainage will be neces- 
sary. Main drains would be laid square to the line of the cutting, 
while diagonal and branch drains would connect with them as 
shown. The size of these drains and the distance apart would 
depend on the quantity of water to contend with and the character 



SLIPS IN EARTHWOKK 



105 



of the material in the excavations, but in ordinary circumstances 
and with, fairly solid material in which to form the drain, the main 
drains would be placed from 20 to 30 ft. apart, and be 2 ft. wide 
by 2 ft. deep, or deeper if necessary in order to get a grip of the firm 
ground underneath. 

The drain would consist of a pipe preferably with spigot and 
faucet joints surrounded on both sides and on the top with broken 
stone carefully hand packed in the trench. If the ground in which 
the pipes are laid is of a clayey description the joints would be 
formed as already described, with clay or cement for the lower 

Surface of ground 



Porous Sirs turn. 



A 



/ \ 

/ N 

/ N 

' ^1 

Jt 


/ 

/ ^ 

\ 


/ 
/ 

\ 

of Railway, 


/ \ 
( \ 


r- 

rmation trevtt 



Slope Drains discharge info<Pjp$orOpen Channel alongside Railway. 
FIG. 58. Slope chains in cutting. 

half, so as to prevent leakage of water which would cause damage 
to the ground underneath, and the trench would be made up on 
both sides of the pipe to the same level as the clay or cement of 
the joint, with clay well rammed in. In good ground, such as firm 
sand or gravel, or with certain kinds of clay, where any little 
leakage from the drain is not injurious to the slope, it would be 
imfficiexit to lay an open-jointed tile drain surrounded by broken 
atones, but in a soft material or material which is easily turned to 
silt or slurry by the action of water, the method referred to would be 
Adopted. 

It is necessary, in forming slope drains, that the drains and 
broken stones be laid immediately after the track has been cut> 



106 EARTHWORK IN RAILWAY ENGINEERING 

as otherwise the sides of the track may fall in and seriously damage 
the portions of the slopes on either side immediately adjoining. 
In addition to taking away the water which appears on the slopes, 
the drains so formed will be helpfnl in supporting the portion of the 
slope between each of the main drains. These drains would, of 
course* not be laid until the slopes of the cuttings had been formed, 
but in view of the importance of keeping the embanking material 
as free as possible from water, it is most essential that any water 
met with should be temporarily led away in pipes or timber troughs 
or other channels while the excavation work is in progress and 
before any damage can result to the slopes. 

When the slopes of the cuttings are subsequently being soiled, 
care should be taken by covering the drains with bags or otherwise 
to ensure that the soil is not allowed to mix with the broken 
stones, and thereby reduce the efficiency of the drains, and for 
the same reason the broken stones should be carried up to the 
level of the surface after the slopes have been soiled. 

In addition to the main and diagonal drains patches of pitching 
may be necessary to drain any soft portion of the slope that may 
have a tendency to slip. It is better that the diagonal drains 
should not be laid with too flat an angle as there would be a 
tendency for the soil on the upper side to choke the drain, and 
there is also a liability for the drains to become distorted and 
leak when any slight movement of the surface takes place, 
thereby causing the material on the lower side to be washed away 
and the drain ultimately to become destroyed for want of support. 
A very satisfactory result, and that with little extra expense being 
incurred, is obtained by placing a layer of turf along each side of 
the drain and at the level of the soiling, the turf being held in posi- 
tion by wooden pegs if there should be a tendency for it to slip on 
the slope* 

The slopes of ,a cutting are never thoroughly satisfactory until 
they have been soiled over and sown down with grass and a good 
tough sward formed. The roots not only form a binder to assist 
in sustaining the material, but they are also a protection a*gain$t 
wind on a sandy surface, and against rain, which will damage a 
clayey, sandy, or other surface, in which the material, when satur- 
ated with water, has a tendency to ** run." If it is omsidered 
necessary, stronger roots can be obtained by sowing the slopes 



SLIPS IN EARTHWORK 107 

with whin or bioom seed, in which case a very firm deep-rooted 
covering is obtained* 

In the case of cuttings which consist of certain kinds of clay, 
where the material, when protected, will stand at the usual slope 
of 1| to 1, what is wanted is more of a covering with close binding 
roots, and where water falling on the surface will drain freely off, 
and in such cases whin or broom would be objectionable. In sowing 
slopes it is necessary that the work be executed at the proper 
season of the year so as to ensure a good growth being formed 
before wintry or otherwise inclement weather. To maintain the 
slopes in good condition the grass or broom should be cut 
periodically. While it is right that the slopes should be dressed to 

tone c/rstns Prom 
y 'to 40 'apart 




FIG. 59, Large slope drains with toe wall at foot of dope. 



a regular batter, it is a mistake to have ioo smooth a surface, as 
the soil may get washed off by the first rainstorm and before the 
roots of the grass covering are developed* 

When the excavations consist of soft clay or other material 
which, when in its natural moist condition may stand at a slope 
of 3 horizontal to 1 vertical, but when saturated with water 
may run to slurry, more expensive works than those referred to 
will be necessary. The action of rainstorms on slopes of this 
class of material, even after being covered over with grass, may 
be most destructive. In dry weather the surface gets cracked and 
open which gives access for water in wet weather, thereby causing 
the damage. When adjoining property is valuable and where the 
cutting is not more than a few feet deep, it may be more economical 
to build retaining walls for the full depth of the cutting. If the 
Adjoining property is not expensive the material might be allowed 
to take its owxt dope. 



108 EAUTHWORK IN RAILWAY ENGINEERING 



If the cutting is over a few feet in depth, while the cost of the 
land may not be of serious moment, to allow the material to adapt 
itself to a natural slope might, owing to the configuration of the 
ground, be entirely out of the question, and with the view to bring- 
ing the work within reasonable limits it may be decided to drain 
the slope in a somewhat similar manner to that already described, 
but on a larger scale. Drains of from 4 to 6 ft. wide and from 2 to 
3 ft. deep placed from 20 to 40 ft. apart would be constructed 
(see Fig. 59) with a toe wall carried along the foot of the slope 
continuous between the drains, The stones used for these drains 
should be fairly large but not too heavy, otherwise the soft slope 
would not be able to support them ; but, on the other hand, they 
should be such that the pressure of the material behind will not 



/Soil 




y-xs ^^j. 

Slope drain/ N o c ^ ^J|3P 



Turf Cope 

Dry s tone Wall 



^ Ditch 
0* Brystone clwarf wall at foot of slope. 



force them out of place. If the clay from the cutting of the drains 
is suitable, it would be burned and the clinker used for filling the 
drains, or old slag ballast or other light material would be very 
suitable. To protect the exposed clay from the effects of warm 
weather and subsequent rains, it should be covered over with 
ashes, gravel, or similar material to a depth of at least a foot, and 
afterwards soiled over. 

The method adopted for dealing with slipping material in clay 
cuttings is largely determined by the cost of removing the material 
and forming drains and revetment walls, together with the cost 
of the land, as against the cost of building substantial retaining 
walls. 

In all cuttings through material other than rock the toe of the 
slope alongside formation would be protected from erosion by water 
flowing ofi the slope and running alongside formation. In very 



SLIPS IN BAETHWOEK 109 

shallow cuttings a turf border 18 in* broad laid in two thicknesses 
may be sufficient, but where over a few feet in depth it is usual to 
form a drystone dwarf wall (see Fig. 60). The deeper the cutting 
is the greater will be the volume of water running off the slope in 
wet weather, and consequently there is the greater necessity for 
the toe of the slope being well protected in deep cuttings. If a 
wall is constructed ample provision should be made for the free 
passage of water through it, and a drystone wall would thus be 
preferable to a wall built with cement, where the wall is of a less 
depth than 5 or 6 ft. Where the wall is built with cement a 
thickness of 12 or 18 in. of drystone backing should be placed 
behind it, with proper connections made to the drainage outlets 
in the wall. These outlets or weep holes should not be more thaa 




Loose Rock 
> 61. Flat slope in loose rock cutting. 

about 9 in. below the finished level of the rails adjoining, so as to 
ensure that there will be no obstruction at the outlet end of the 
pipes. 

Slips in rock cuttings are generally due to the inclination of "the 
beds of stratified rock which may be such that when cut through 
the portion on the upper side of the " dip ** falls away for want of 
proper support, and, if water should have found its way into the 
strata, there will be the greater tendency to slip. 

Slips are of most frequent occurrence in strata consisting of thin 
layers of limestone or faikes intermixed with bands of clay or silt. 
Overlying this there may be a porous stratum, from which water 
finds its way through the fissures in the rock until a solid impervious 
stratum is reached. When such material is cut through the water 
will trickle down the face of the cutting over the exposed ends of 
the strata, washing out the beds of clay or silt near the face, and 
thereby toidermining the thin layers of rock overhead, which will 
fall in. Changes of weather, frost, thaw, and rain, will 



110 EARTHWORK IN RAILWAY ENGINEERING 

assist tiis disintegrating action. WMle the presence of water con- 
siderably hastens the destruction, atmospheric influences alone 
would slowly cause the exposed face to corrode, and unless other- 
wise protected it would probably be necessary to take out the 
excavations to a slope of 1 J to 1 if the beds of the strata are level, 
and if they should be at even a very slight inclination it may be 
necessary to finish off the slope by stepping back the broken rock 
to a batter of perhaps 2J to 3 to 1 (see Fig, 61). If it should be 
necessary to flatten the slopes beyond what was originally intended 
additional land will have to be acquired or face walls of sufficient 
height built to keep the top of the slope within the limits of the 
original ground. The method adopted will altogether be decided 



Brick facin 

c&ncrete 

behind 




* 'Ditch 
FIG. 62. Face wall in rook cutting. 



on the question pf expense, and in considering the matter it must 
be kept in view that it will be less costly to maintain a retaining 
wall than a slope which may require frequent attention. 

When on account of the character of the material it is necessary 
to excavate the rock to a 1 to 1 batter or to a flatter slope, a 
covering oi grass will prove a sufficient protection from the action 
of the weather ; but, if the material will stand at a steeper slope 
without risk of sliding, a face wall would be constructed* ample 
provision being, of course, made for free drainage of any water 
that may collect at the back of the wall* Figs* 62 and 63 illustrate 
a face wall and a retaining wall respectively to protect or support 
a rock oatting* 

As regards the treatment of slips, no hard and iasfc stab can be 
laid down, as each failure must be dependant on tke particular 



SLIPS IN EARTHWORK 



111 



circumstances tliat surround it. By noting, however^ tlie means 
generally adopted and the manner in which special cases are dealt 
with, a method of procedure may suggest itself. 

When considering the means taken to prevent slips the necessity 
for thorough drainage was pointed out, and the inefficiency of these 
protective measures is very largely responsible for the slipping of 
material in slopes. It will be obvious that by giving due considera- 
tion to the question of drainage much of this trouble may be averted, 
but it must be admitted that serious damage may occur by circum- 
stances that could not have been foreseen. It is necessary to 
emphasize the importance of frequent observations being taken if 



,$tane Cope 



Stone facing with 
concrete backing 




FIG. 63. Retaining wall in soffe rock cutting. 

there is any probability of a slip taking place, and when any water 
appears or collects on the ground or when there is the slightest 
indication of a movement in the ground, the warning should not 
be neglected, but instant steps taken to avert what might mean 
very serious trouble. These remarks apply equally to slips in 
embankments as well as in cuttings. 

When a slip does take place in a cutting endeavour should at once 
be made to divert any water that may flow into the back of the 
moving material, and such, temporary work as the lightening of 
the upper portion of the disturbed mass and the supporting of the 
mmoved ground behind should also receive immediate attention. 

When the damage done is of small dimension the slipped material 
s|fOiild W cleared out to the bottom (see Fig. 154), following on 
tjbte surface underneath should be covered over with large 



112 EAETHWOEK IN RAILWAY 



stonec, carefully hand placed^ and a drain laid therefrom to the 
ditch or water channel which runs along formation* Quarry 
shivers or old slag should afterwards be placed on the top of this 
layer of stones and brought up to the level of the surface of the 
slope ; the upper surface should thereafter be blinded with finei 
material and finally soiled over and sown down. Care should be 



Stone filling 




Dra. 



Side drain j 

FIG. 64. Slip of small dimensions in cutting. 

taken to ensure that the stone filling is built close up to the back 
of the slip, and any water in the exposed stratum should have free 
drainage to the drain pipes leading to formation of the cutting. 
Surface cracks which may subsequently appear, due to settlement 
or after heavy rains, should be made good with a view to preventing 
further damage. If the material under the slip is of a soft descrip- 
tion* the filling in should be of a light character. 




Stone drffnpr counter Fort (trystone walll 
' r wde t pfoc&dfrom 20 to SQ'bpart. 



Sof/d 
grow 



Fio. 65. Slip of large dimensions in cutting. 

More extensive slips may be due to the complete saturation of the 
materials in the slopes and the consequent tendency to take up a 
horizontal position. In such cases an attempt should be made to 
restore the material to its original stable condition by constraotimg 
heavy slope drains and forming a strong toe wall in the 



already referred to for dealing with soft cuttings, In certain 
strata it is a common occurrence for the slipping material to oome 
away from the solid ground in a plumb face (see Kg. 6fi). 



SLIPS IN EAKTHWORK 113 

strata may consist of clay with, thin layers of sand interspersed, 
or it may be beds of limestone and faikes or clay in alternate 
layers, and the movement will probably be caused by water perco- 
lating through the sand or open joints of the broken rock, saturating 
the clay bed and converting it into silt or slurry. Slips of this 
description have been successfully treated by constructing stone 
drains or counterfort drystone walls at right angles to the line 
of the cutting. The trenches for the walls would be cut down to 
and into the solid ground underneath and carried to the solid 
ground at the back of the slip. These walls when formed will act 
both as a carrier for the removal of water and as a support for the 
unmoved ground behind. The width and distance apart of these 
walls will depend on the character of the slipping material and the 
depth of the slope ; but in general they might be from 4 to 6 ft. 
wide, and from 20 to 50 ft. apart. There is a danger of having 
them too far apart, as each portion of the slope between the walls 
may have a tendency to slip of itself. Surface diagonal slope drains, 
2 or 3 ft. square, may be laid between the walls to consolidate the 
ground more effectively and prevent further slipping ; but if the 
slope has been very badly shaken it may be necessary to turn over 
the whole of the material between the walls and compact it by 
wheeling and punning, and the surface should thereafter be covered 
with a bed of ashes under the finished coating of soil, so as to 
protect the clayey material underneath from the action of the 
weather. 

To further support the slope a drystone wall should be constructed 
alongside formation, connecting the ends of the counterfort walls, 
through which the drains from the slope would be carried into a 
main drain laid alongside the track. If the excavations from the 
drains should consist of suitable material it may be economical to 
burn it into clinker for use in the walls and drains. In the event 
of the damage being caused by surface water, a pipe would, as 
already stated, be laid as BOOB as the slip is observed to divert the 
water ; but if the water is in the strata, it may be advisable to lay 
a dmn clear of the slip in addition to the other remedial work 
referred to. 

!Efce foEowing is an instance wherein circumstances necessitated 
spe^aal treatment (see Fig. 66). 

&&& .cutting was for the construction of a railway and had a depth 



B.2UL I 



IU EABTHWOEK IN RAILWAY ENGINEERING 



of 29 ft- measured on the centre line ; but by reason of the inclina- 
tion of the surface of the ground, which was about 4 J horizontal to 
1 vertical, the vertical depth from the top of the slope to formation 
level was about 70 ft. The material cut through consisted of moss 
for the first 5 ft., underneath which it was of a greasy clay until 
formation was reached, when faiky fireclay was met with. The 
material was being excavated to a slope of If horizontal to 1 







7 






I 



I 1 



r ^^^^^^~ 




Section A B. 

66. Slip in cutting requiring Special treatment 



vertical, and the cutting had been excavated to within 5 ft* 6 in. of 
the formation level, the slopes being dressed off to the finished batter 
immediately behind the steam digger, when without any previous 
warning the ground on the high side gave way. The plane on which 
the mass of clay was sliding was inclined at about 2 to 1, and the 
disturbed ground extended for a width of about 165 ft* outside of 
the top of the slope. 

Arrangements were at once made to remove the whole of the 



SLIPS IN EAETHWOEK 



115 



slipping material, and simultaneously a concrete wall was built in 
trenches for the support of the lower portion of the cutting which 
had not yet been removed. The wall was built in sections of 12-ft. 
lengths and was carried on from both ends and at varying stages 
of progress so as not to disturb the unmoved ground behind, and, 
as a protection against the wall being pushed out after the lower 
portion of the cutting had been removed, bands of concrete were 
carried across formation to the foot of the opposite slope. After 
the slipping material had been removed and the rough edges round 
the slip dressed off to a regular slope, the area was soiled over 
and sown down. 

The following special measures were adopted in excavating a 
railway cutting where a large volume of subsoil water was present, 




8 / 



1 3Prpe ^Sky ballast V ^StoneShivers 

FIG. 67, Section in cutting with large volume of subsoil water. 



which will illustrate the means adopted to prevent subsequent 
slipping (see Pig. 67). 

The cutting was 43 ft. deep, and the stratum consisted of fine 
sand and contained a large volume of water. As the work proceeded 
the water in the sand was lowered until it reached a level of about 
6 ft. above formation level of the railway, below which the material 
consisted of fine sand and mud, of a very wet consistency, The 
cutting was taken out to* a depth of 2 ft. below formation level and 
a tfow of sheet piling was driven along each side of formation. 
These piles were 8 ft. long, 12 in. broad by 6 in. thick, and were 
driven so that they would have 4 ft. of a hold below the level 
excavated, and to allow of water getting through from behicul, 
a distance piece | in. thick was fixed to the side of each pile. The 
space at the back was filled with stone quarry shivers and oovered 
over with ashes. 



116 EARTHWORK IN RAILWAY ENGINEERING 

At certain points the flow of water in the sand behind the piles 
was stronger than at others, and at these places open-jointed 
fireclay pipes were laid and carefully surrounded with stones. The 
space, which was taken out 2 ft. below the formation level between 
the fronts of the two rows of piles, was filled up with ashes, and a 
9-in. open-jointed pipe was laid along the front of the piling on 
each side of the railway and covered over with broken stones. 
The slag ballast of the railway was carried level across between 
the piling and this assisted the keeping of it in position. The 
slopes of the cutting were afterwards dressed and soiled and 
sown down with grass seeds, a double turf cope being laid along 
the top of the piling. As indicative of the quantity of water met 
with, it may be remarked that each of the 9-in. pipes was running 
half full for a considerable time after the work was executed. 



SLIPS IN EMBANKMENTS 

Slips in embankments are either due to the character of the 
material of which the embankment consists or the condition of the 
ground or of the substratum under the site of the embankment- 

As regards the former, while the description of the material as it 
appears in the cutting is the primary consideration, the manner 
in which it has been removed from the cutting and deposited in the 
embankment, together with the weather conditions when the work 
was executed, may be very largely responsible for the stability of the 
work. 

Prom an economical point of view, it is generally desirable that 
the quantities of the cuttings and embankments should as nearly 
as possible balance, but an embankment must not be endangered 
by depositing other than the most suitable materials, and conse- 
quently all wet sand, mud, moss, or material of a gi.miH.aT description 
should be run to spoil. 

By reason of the fact that the cohesion of the material which 
existed in the solid cutting has been largely reduced when the 
excavations were being removed, the supporting power of the em- 
banking material immediately after it has been deposited is for the 
most part obtained from the factional resistance between the 
particles or pieces forming the mass. The original cohesive resist- 
ance can, however, in a large measure be restored if care is taken 



SLIPS IN EAETHWOEK 117 

in depositing the excavations in, embankment ; but in view of the 
vibration caused by suddenly applied loads such as occur on rail- 
ways, it is not desirable to put too great reliance on the additional 
stability so obtained. 

In forming an embankment water should, as far as possible, be 
kept clear of the operations in the cutting from whence the material 
is obtained, and precautions should also be taken to prevent any 
lodgment of water on the surface of the embankment. A good deal 
depends on the time of the year when the work is being executed, 
but neglect in making proper provisions for drainage is accountable 
for many slips in embankments. A little rain will assist in con- 
solidating an embankment, but a continuous spell of wet weather 
will tend to cause slipping. 

When operations are resumed after having been suspended on 
account of inclement weather, clayey material which has been 
converted into slurry at the point where excavations were pro- 
ceeding, as well as similar material on the surface level of the 
embankment where the excavations are being deposited, should 
be removed and run to spoil. If the operations have been con- 
ducted during a very dry season, moisture in the excavated material 
will be dried out, with the result that when wet weather sets in 
damage may be caused by reason of the swelling of the mass. 
Sand or gravel, or similar material, will be much less affected than 
clay, faikes, or material of a like description in which the particles 
are dissolved by water. In clay embankments fissures and cracks 
which are formed during a dry season should be filled up so as to 
avoid damage when wet weather sets in. 

When the excavations consist of hard clay, or boulder clay, it 
may be advantageous to loosen it by blasting immediately ahead 
of where the steam digger may be working, and there will probably 
be large lumps of material which, if tipped into the embankment 
without first having been broken up, will cause trouble, as surface 
water will get into the crevices, the clay will soften, subsidence 
take place, and finally a serious slip may result* When the material 
is being deposited, the larger pieces of it roll to the bottom of the 
slope, and if these should consist of large stones or pieces of rock 
they will assist in maintaining the toe of the slope ; but if they 
should be pieces of clay, instead of acting as a support they wiE 
eaofce serious trouble. 



118 EARTHWORK IN RAILWAY ENGINEERING 

Embankments of earth should be as homogeneous as possible, 
and this Is best obtained by bringing them up in several layers 
when they are being formed in the manner already described. 
The advantage to be gained in using side-tip wagons in prefer- 
ence to end-tip wagons in forming wide embankments has already 
been referred to. A method which has been successfully adopted 
in constructing wide banks is to tip a narrow bank of good 
material at the extreme outsides and afterwards fill in the centre 
portion with whatever material was available ; but this departure 
from the recognised principle of running bad material to spoil 
should only be resorted to when suitable embanking 'material cannot 
otherwise be obtained. 

When various classes of material are put into the same embank- 
ment, or when the work is carried on during different kinds of 
weather, some parts of the embankment will be more compact than 
others, and consequently there will be a want of proper homo- 
geneity, with the result that there will be a tendency to slip. It 
may be very difficult to obtain the same material to fill a 
embankment throughout. Several cuttings may be required 
make up one embankment, and even the material in a large 
may vary considerably at different points, but if it Is carried up 
in layers, thus ensuring that each layer consists of the same material 
or is executed during the same season, there will be less chance 
of damage from that cause. 

It is essential that the slope of the embanking material be not 
made steeper than the slope to which the cutting from which the 
material has been removed has been formed, and it is also necessary 
that the slope should be sufficiently spread out so that the unit 
pressure at the base, both on the material in the embankment and 
on the ground on which the embankment rests, will not b too great. 
It will be recognised, however, that it may be -harmful to make a 
slope too flat, for the reason that a larger surface is thereby ex- 
posed, and also that by reason of inequalities in the surface which 
occur in any slope and cause saturation of the material. It is usual 
in high embankments to form the upper part with a steeper slope 
than the portion nearer the base, and this is especially desirable 
in a bank of clay. It has to be kept in view that the material in 
any embankment is not absolutely compact until several years 
have elapsed from the time of it being deposited. 




SLIPS IN EAKTHWORK 119 

In order that a good toe be formed along the foot of the slope, 
the more solid materials in the cuttings should be deposited along 
the outer edge, and it is usual to strip the soil from ofi the area to 
be covered and lay it temporarily along and outside of the foot of the 
slope, where it will form a barrier for the deposited material and 
at the same time be conveniently situated for the subsequent 
soiling of the embankment. On side-lying ground it is desirable 
that a trench be cut in the solid ground along the foot of the slope 
against which the deposited material of the embankment will abut, 
and it is also necessary that longitudinal trenches be cut at intervals 
as has already been described, for the purpose of preventing slipping 
of the material ; but any trenches so formed should not be exe- 
cuted for any lengthened period previous to the embanking material 
being deposited, as otherwise if wet weather intervenes the base 
of the embankments will be weakened rather than strengthened. 
The importance of taking away water frdm the foot of a slope 
and thereby ensuring the stability of the embankment at its most 
vulnerable point will be appreciated. 

As in the case of cuttings, the formation of a good sward of grass 
is most effective in preventing damage by the percolation of rain 
or surface water, or by the action of wind on a newly formed 
slope, and no time should be lost ia having the slope soiled. An 
embankment formed of clay can never be considered satisfactory 
until a good growth of grass covers the surface. In the case of 
sand or gravel water will pass through and drain itself off, but in 
the case of clay the water is retained and the clay will take a flat 
slope. A layer of good turf along the top of a slope will form a 
protection against the upper portion being damaged by the action 
of rain on a bank which has been recently soiled. While it is 
undesirable that the slopes of a Mgh embankment should be soiled 
until it has been raised to the fuU height, it is better that they 
should, at least be roughly dressed off to the finished batter as the 
wprk proceeds, and this is more especially necessary in the case of 
a clay embankment. 

The upper surface of an embankment should also be impervious 
to water, and this is weE obtained by the constant traffic which 
passes over it while the work is in progress, and as a precaution 
w&ter getting into the bank from the top the upper layer 
consist of thje more conapaqt materials from the excavations, 



120 EARTHWOBK IN RAILWAY ENGINEERING 

and so that there will be no lodgment of water on the surface it 
should be finished off with a slight cross-fall from the centre to each 
side* In the interest of the stability of an embankment for a rail- 
way it is not desirable to make the formation too narrow so that 
there will be the less tendency for the top of the slopes to give 
way by reason of the traffic. When any settlement takes place after 
heavy rain or frost or thaw, any crevices that may be formed should 
be immediately restored with impermeable material* 

While slips in an embankment, due to the material of which 
it consists, can in a large measure be prevented if proper pro- 
visions are taken, those due to the character of the ground on which 
the embankment rests are much less easily obviated. The site of 
the embankment may consist of moss, soft clay, or other similar 
material, and any weight brought on to it will tend to displace 
this material. When this soft stratum is of no great depth and 
the surface of it is level, or nearly so, no damage will result beyond 
the displacement of the surface, and the embanking material will 
soon find its bearing on the solid ground underneath ; but if water 
should be present in the soft material, as will probably be the case, 
constant trouble may result if the ground has not been drained 
prior to the embankment being proceeded with. Any water on 
the site will cause the embanking material to spread out to a flat 
slope, and if clay or other similar material is deposited it will be 
turned into slurry, thereby causing a slip. The material on the 
site may be such (as in the case of some clays) that no amount of 
drainage will make it suitable for carrying an embankment, in 
which case it will either be necessary to drive sheet piling along title 
toe of the slope to prevent it spreading, or to excavate the material 
from under the site of the embankment and run it to spoil. 

Where piling has been driven the pressure of the substratum has 
been known to shear ofi the piles at the level of the solid ground and 
carry them bodily forward for a considerable distance. The removal 
of the bad material to spoil will probably be an expensive operation, 
but it will certainly be the more effectual. In certain situations 
it may be impossible to thoroughly drain the site, and in such cases 
by depositing ashes, old slag, gravel, or other material that will 
not " run " on the top of the soft material on the site, the latter 
can be displaced and a solid foundation obtained, and, after the 
ashes or other materials have been raised to the level of tlie 



SLIPS IN EARTHWORK 



121 



original surface, the ordinary excavations from the cutting can be 
deposited. 

In the event of the site being drained, the drains should be of 
a massive description and be laid either in diagonal trenches or 
square to the line of the bank, having an outlet into main drains 
formed along the outside of the slopes. These drains will be carried 
down to the solid ground, and those along the foot of the slopes 
will be of such dimensions as would also act as a retaining wall 
against which the embankment would abut. The material from 
fche excavation of the drains could, if suitable, be burned into 
clinker and used for the drystone filling of the drains. If the 
depth of the soft strata on the site is such as to preclude the possi- 
bility of thorough drainage, the embankment would req.uire to be 



River* 




Trenches filed with 

stem 6ft. wide at 

50ft, apart 



FIG. 68. Slip in embankment on side-lying ground* 



supported on fascines, as has already been described in connection 
with embanking over moss land. While the surface of the moss 
or sofb material may be level, the firm ground underneath may 
be lying at an angle, and unless proper provision, such as has 
been referred to, is carried out serious slipping may result. 

The embankment may require to be formed on side-lying ground 
of such.-a character that the material under the surface is in a state 
bordering on motion, and when any additional weight is applied 
slipping will take place. The unstable description of the ground 
may be due to the presence of water in the material lying under the 
surface, or to water acting on a greasy bed underneath, and the 
drainage of the site or the interception of the drainage from the 
adjoining land may be effective in converting tie site into a good 
condition. 



122 EARTHWORK IN RAILWAY ENGINEERING 

The following example will illustrate this point (Pig. 68). The 
ground on which the embankment was to be formed showed signs 
of slipping having taken place at a former period, and the stratum 
under the surface was of a very soft character and side-lying at an 
inclination of about 2 J horizontal to 1 vertical. Trenches 6 ffc. wide 
were cut on the side-lying ground at right angles to the line of the 
railway at intervals of 60 ft., and were carried down to the solid 
ground underneath, which, in some places, was at a depth of 20 ft. 
below the original surface, these trenches being afterwards filled with 
large stones. Between these drains benches of 4 ft. wide by 3 ft. 
deep were cut at intervals on the sloping ground parallel to the line 
of the railway, and a heavy retaining wall was also built along the 
foot of the embankment, which, in addition to supporting the slope, 
acted as a training wall for the adjoining river. The excavated 
material from the line cutting was then deposited in regular layers 
and thoroughly consolidated between the drains and behind the" 
walls. 

In such cases as that last referred to, where there is a solid stratum 
of either rock or good material under the slipping material, it may 
be more economical to construct retaining walls alongside foffym* 
tion to support the railway, or it may be considered better to carry* 
the railway on a series of arches. By adopting either of these 
expedients, the first cost may be more, but by reason of the subse- 
quent maintenance of the earth slope being avoided the alternative 
schemes may be justifiable. 

When an embankment is being formed on good ground a thorough 
examination of the surface should be made so as to ensure that there 
is no water coming to the surface from natural springs or drains 
which have not been properly intercepted. Any water that does 
appear should, if possible, be caught up outside the embankment 
slopes, but failing this it should be conducted by iron pipes or 
built conduits entirely clear of the operations. If the ground is 
side-lying, water may be percolating from the outcrop of a stratum, 
and it should be intercepted by a drain outwith the embankment, 
in a manner similar to what has already been described in connec- 
tion with the protection of cuttings. 

The following example will illustrate this point (see Fig. 69) : 

The stratum immediately underneath the surface soil was of 
a gravelly description, while underneath the gravel was clay at 



SLIPS IN EARTHWORK 



123 



varying depths. Tlie water in the gravel was held up by the clay 
and made its appearance on the surface of the ground on which 



CQJ 






c 

W 



the railway was to be formed. With a view to intercepting this 
a^ a drain was cut along and outside of the fence on the upper 



124 EARTHWOBK IN BAILWAY ENGINEEBING 

side of the railway. The drain was in some places at a depth of 
about 25 ft. A pipe was laid in the bottom immediately on the 
top of the clay, the joints being left open and carefully packed 
round with broken stones. The trench was filled to the surface 
with stones, and all field drains intercepted were connected to this 
main drain. Owing to the irregular line between the gravel and 
the clay there had to be two outlets, one running parallel to the 
railway, the other carried underneath the embankment on the side- 
lying ground. 

This latter drain consisted of cast-iron pipes supported with 
concrete blocks at the joints. A heavy retaining wall was built 
along the foot of the slope, and benches were cut in the side-lying 
ground, after which the embankment was formed* When the 
embankment had been brought to the full height, some water, 
which had not been diverted into ,the intercepting drain, appeared 
at places on the surface of the slope, and several minor slips took 
place. Four drains 7 ft. wide by 7 ft. deep were then carried 
up the slope of the embankment at intervals of about 30 ft. and 
filled with heavy stones to the surface, and the slopes were 
thereafter soiled and sown with grass seed and mixed with 
broom. A good sward was soon grown, and no further trouble 
was experienced. 

In the construction of a railway or road in side-lying ground 
where the earthwork is partly in cutting and partly in embankment, 
great care should be observed to see that water from the cutting 
on the upper side should not be allowed to percolate under the 
embankment on the lower side, and it is necessary that the drainage 
of the adjoining land, as well as the drainage of the slopes of the 
cutting, should be properly attended to. 

The remedial work required in the event of a slip in an embank- 
ment due to the material of which it is constructed consists of the 
removal of the water which has been the cause of the damage or 
the supporting of the slope in a manner somewhat similar to what 
has been described when referring to slips in cuttings. In an 
embankment, however, operations are not so restricted at the foot 
of a slope as they are along the formation line of a road or railway 
when the construction is in cutting, and it is thus unnecessary to 
remove the slipped material from the foot of the slope unless it is 
encroaching on adjoining property. 



SLIPS IN EABTHWORK 125 

Surface slope drains or drystone counterfort walls carried down 
to the solid and a good strong toe wall built along the foot of tlie 
slope should be constructed as required. It is better that the 
slipped material should not be removed, but be allowed to remain 
at the angle of repose that it has taken, and if there should 
be intrusion on adjacent lands a wall may be required to support 
the lower portion of the slope or additional property may be neces- 
sary. Serious slipping in an embankment has been effectively 
stopped by loading the toe with heavy stones, thus arresting the 
outward movement. 

Water getting into the heart of an embankment has frequently 
taken place by reason of fissures in the upper surface ; this may 
be the cause of periodical slipping and will give constant trouble 
unless it is effectively dealt with. In such a case a drainage heading 
or series of drains driven into the bank would remove any water 
which had collected or was in the material, and it would also be 
necessary to remove part of the upper surface of the embankment 
and replace it by good material. 

A case is reported where a bank 60 ft. high, formed of dry sand 
and gravel slipped by water appearing on the surface of the slope. 
The ballast and permanent way of the railway had been laid and, 
when investigation was made, the damage was traced to the manner 
in which the surface of the embankment had been executed. The 
formation of the railway had been formed to the usual cross-fall 
for the purpose of draining off surface water, but the subsequent 
settlement of the embankment necessitated a greater depth of 
ballast being laid to bring the railway to proper level. For the 
sake of appearance the bench between the foot of the ballast and 
the top of the slope on either side has been made up with slag 
riddlings, which prevented the free drainage of the surface of 
formation, with the result that instead of the water running ofi 
the slopes it was held in a hollow under the rails, thereby finding 
its way into the sand and gravel and causing the slip. 

Embankments have been known to slip after a number of years 
through water, which had no means of escape, having collected in 
the heart of the bank, and on a drain being formed to the seat of 
the trouble the Ttfater found an outlet and the slipping ceased. 

Sips due to bad material being deposited in embankment are 
sometimes very troublesome, and there are cases on record where 



126 EARTHWORK IN RAILWAY ENGINEERING 

an entire bank has had to be removed and mn to spoil. The 
material of which it was constructed appeared to be quite good 
when deposited, but after wet weather set in it was converted into 
slurry. 

If the slip should be due to unequal settlement of the embanking 
material, the fissures which are formed on the surface should be 
closed up, otherwise the embankment may be completely rent in 
two. In such cases, after settlement has taken place, the upper 
portion of the embankment for several feet in depth should be 
removed for the full width, both of the stable and unstable material, 
and the bank thereafter brought up to its original level by means 
of ashes or other dry material, so as to ensure that any load after- 
wards applied to the upper surface will be equally distributed over 
both parts of the embankment underneath. When the site of the 
embankment is unsatisfactory and the preventive measures already 
suggested have either failed or have not been properly executed, 
serious slipping may result. Embankments have been known to 
move for many years after they were constructed, in some cases 
leading to their ultimate abandonment- 



CHAPTER VII 

MAINTENANCE OF EAETHWOEK 

THE more thoroughly the work of constructing the railway is 
carried out the less will be the subsequent cost of maintenance. 

In the preceding chapter the means taken to prevent and remedy 
slips were considered. It was pointed out that the greater number 
of slips were due to the presence of water, and the necessity for 
diverting water away from cuttings and embankments, or of leading 
it away in such a manner as would prevent damage, was emphasised. 
It is necessary, however, that these preventive and protective 
measures should be kept under constant observation, and that 
so soon as any interruption of the functions for which these special 
works were carried out is observed, immediate steps be taken 
to remedy matters* 

The maintenance of railway works is always greater the first 
year or two after the works are completed than during subsequent 
years. 

Special inspection should be made of cuttings and embankments, 
more especially the drainage works, during wet weather or after 
periods of melting snow or abnormal discharge from water-bearing 
strata, when the various drainage works will be fully taxed, and 
this inspection should be carried out in a most thorough manner, 
so as to ascertain what, if any, additional works are necessary and 
what repairs require to be executed. In the case of open ditches 
it will at once be seen where there is any interruption of the regular 
flow, and the ditch can be cleaned out ; but in the case of pipe 
drains, or piping laid in the bottom of stone pitching (or " beach- 
ing 9> ), an obstruction may not be detected until there is indica- 
tion of such on the surface, either in the form of a discharge of 
water or by damage to the slope or surface of the ground. 

The maintenance of the permanent way in first-class condition 

127 



128 EARTHWORK IN RAILWAY ENGINEERING 



9LJ 



TU.-I ~- ,--- 



MAINTENANCE OF EARTHWORK 

is one of the principal duties of the Engineer, and to obtain the best 
results perfect drainage of the formation is essential. 

Water falling on the railway or draining on to it should be 
removed as speedily as possible, and the railway works should be 
designed with this in view. The surface of the formation in both 
cuttings and embankments should haVe a camber or cross-fall 
from the centre to the sides so that water passing through the 
ballast will be shed off, and in cuttings side drains or open ditches 
should be provided for the removal of water both from the forma* 
tion and from the railway slopes. Fig. 70 shows typical cross- 
sections of British main line permanent way. 

The ballast under the sleepers is regarded as the foundation of 
the permanent way ; but the real foundation is the material on 
which the ballast rests, and if it is unsatisfactory the whole object 
of having good ballast is defeated. A good foundation under the 
ballast is of equal importance to the ballast itself. It is thus 
necessary that the material immediately under the ballast he kept 
thoroughly drained, and this is effected by side drains or open 
ditches. 

If water is allowed to collect under the sleepers, or if the material 
under the sleepers retains water, the soft wet material will very soon 
be converted into mud, and will be squeezed through the ballast. 
The result will be that the life of %he sleepers will be very con- 
siderably reduced, the fastening of the chairs to the sleepers will 
be rendered ineffective in a short time, and the permanent way 
generally will be seriously impaired. 

The material under formation may be of such a description that 
it cannot be drained, and any water passing through the ballast 
into it converts it at once into slurry. In this case it will be better 
to remove such material to a depth of 2 or 3 ft., or deeper if neces- 
sary, and replace it by old slag or spent ballast, ashes, or other 
material that will not obstruct the drainage. 

So far as the ballast of the permanent way is concerned it should 
consist of good hard slag, broken whinstone, granite, or other 
material which will permit of free drainage, and at the same time 
give a solid bed for the sleepers. 

Good drainage and good ballast are essentially necessary for 
first-class permanent way. 

Reference was made in the previous chapter to the damage done 

BJUk K 



130 EARTHWORK IN RAILWAY ENGINEERING 

by making up the sides of an embankment where additional 
ballast was necessary to bring the railway to proper level with 
earthy material so as to have a neat and tidy appearance, with 
the result that instead of having a fall from the centre to the sides, 
there was actually a water channel down the centre of the railway, 
which ultimately found an outlet on the face of the embankment 
and caused a slip. It would have been better to have left the edges 
of formation low, although they might have had a slightly ragged 
appearance, rather than interrupt the free drainage of the formation. 
Neatness in maintaining the railway is an indication that the work 
is also being efficiently executed, but if those who are responsible 
for the maintenance of the permanent way do not thoroughly 
appreciate the importance of good drainage, their efforts in 
maintaining a neat formation will be entirely ineffective. 

The object, so far as the drainage and width of a cutting are 
concerned, is to bring the condition of the roadway as near as 
possible to what exists in an embankment where there is free 
drainage and the railway is in the open. 

The formation of a railway in cutting should be as wide as possible, 
so as to obtain proper drainage, and also to get the benefit of the 
drying effect of wind and sunshine. It is a mistaken policy to cut 
down the width of formation at the expense of the maintenance. 
This matter has already been referred to in Chapter I, page 4. 

For the drainage of cuttings an open channel is preferable to a 
closed pipe, as it can be easily cleared of any obstruction. When 
the gradient of the railway is flat and the flow of water sluggish, 
an open channel is easily obstructed by debris, leaves of trees, 
washings off the slopes, and stones from the ballast, and any 
interruption of the flow will tend to weaken the support of the 
ground under the sleepers, and also to undermine the foot of the 
slope of the cutting. For this reason, a pipe would be used in 
preference to an open channel on a flat gradient. Apart from the 
question of the gradient, it may not be possible to construct an 
open channel on account of the soft description of the material, ia 
which case a pipe would be laid. 

When a ditch or open channel is provided it should be formed 
along the foot of the slope, one side of the channel being the toe of 
the slope. The channel would be about 1 ft. to 1 ft. 6 in. wide by 
6 to 9 in* deep* If the material in the bottom of the cutting is 



MAINTENANCE OF EARTHWORK 131 

of a firm description the sides would be able to support themselves ; 
but, so as to form a toe for the bottom of the slope of the cutting, 
a 12-in. depth of stone pitching, with a double layer of turf 1 ft. 6 in. 
broad laid on the top, should be placed alongside the channel. 
Where the material is unstable, the channel would be lined with 
stones on both sides. In the case of cuttings over 15 or 20 ft. deep 
where a large volume of water may have to be dealt with, it is 
usual to have a low drystone wall along the foot of the slope, with 
the channel formed immediately in front. 

When, instead of an open ditch, a pipe is laid alongside formation, 
the top of it should not be less than 9 ins* below formation, and 
so that there will be free drainage into it, and that no water will get 
out of it to the damage of the ground underneath, the joints should 
be cemented or formed with puddle clay to the level of the horizontal 
diameter, while the upper half of the joints should be left open. The 
filling in of the trench should be carefully and firmly packed up to 
the same level as the sealed half of the joints of the pipes with 
clayey material. Above this level the joints should be carefully 
surrounded with broken stones and the trench filled to formation 
level with broken stones. The upper surface at formation level 
should be finished off with slag, or broken stone screenings, thereby 
ensuring that any water running of the permanent way or off the 
slopes will drain into the pipes. The pipe gratings should be placed 
at intervals along the edge of formation. Inspection chambers 
should also be provided on the Hne of the pipe at intervals of 
about 80 yards, and to allow for any stoppage in the flow of the 
pipe cross pipes connecting both sides of formation should be laid 
at every second or third inspection chamber. 

It should be kept in view that the drainage works in a cutting 
are as much for the purpose of keeping the material under the 
railway in a good condition as for the removal of water which falls 
on the surface. 

It is very important that the slope of the open channels or pipes 
in a cutting should be as steep as possible as, if the water which has 
been collected into them is not expeditiously removed, considerable 
damage may result* In long cuttings the water-course may be made 
slightly steeper than the railway cutting on one side of formation, 
tod connected at intervals by cross pipes to the drain at the foot 
of tlte opposite dope. Connections should be made to the nearest 



132 EARTHWORK IN RAILWAY ENGINEERING 

outlet, and the water conveyed in properly formed ditches or in 
pipes entirely clear of the railway embankment. If it is merely 
allowed to discharge on to the ground and run along the foot of the 
embankment serious damage may result by eating away the toe 
of the slope, or what may be very much worse,, the water may 
find its way underneath the embankment. 

For the purpose of obtaining a fall for drainage, it is better 
that the railway in cutting should be constructed on a gradient. 

The Pennsylvania Railroad Company, America, has given con- 
siderable attention to the question of maintaining the road-bed at 
high standard. A part section of their cutting is shown at Fig. 71. 
The distance from the outer edge of the ballast to the foot of the 
slope is 5 ft. 6 in., and the side ditch is formed by having an even 
fall froni the ballast to the foot of the slope of the cutting, the 




4 

FIG 71. Part cross section of Pennsylvania railroad, America. 

bottom of the ditch being 1 ft. 5 in. below the bottom of the ballast 
at the edge. The slopes are protected from erosion by being turfed, 
and, where necessary, drystone toe walls are built. With so 
great a distance from the ballast to the foot of the slope, no damage 
results to the ballast even with the railway on a very flat gradi6nt. 
The whole object of the greater width is to obtain good drainage, 
with a view to keeping down the cost of maintenance. The 
cost of maintenance is, no doubt, considerably reduced, but the 
extra cost of construction is great. The cost of the additional land 
required for the greater width has also to be considered. 

Reference has been made to the importance of having a good 
sward of grass on the slopes of cuttings and embankments. Having 
got this, it is necessary that it be kept in good condition by having 
it regularly cut or burned. In open country where passing through 
agricultural land, it is a common practice to let the adjoining 
farmers have the grass off the slopes for a nominal rent, conditionally 
that they keep the slopes regularly cut. Where the Eailway Com- 
pany's own men attend to the slopes it is usual to burn the gra$s, 



MAINTENANCE OF EARTHWORK 133 

and this, while keeping the grass short, also provides a manure 
which strengthens the roots. 

The ends of all culverts should be regularly cleared of all debris, 
branches of trees or other material which may have collected in 
the culverts, and which cause stoppage or interruption to the 
regular flow of the stream. 

To protect the railway where in cutting from being blocked by 
snow drifts it is usual to erect sleeper fencing on one or both sides 
of the line where considered necessary. An additional line of 
sleepers placed about 15 ft. distant would be a further protection. 

In countries subject to very heavy falls of snow endeavour is 
made to have the line of railway altogether in embankment, but 
where cuttings are unavoidable it is usual to protect the line of 
railway from being blocked by having snow sheds erected where 
the blocks are likely to take place. These sheds consist of open 
framework covered over either with wood or corrugated iron 
sheeting. 

In rock cuttings where stones are likely to become detached by 
reason of frost and subsequent thaw and which would cause an 
obstruction to the railway traffic, an arrangement has been success- 
fully adopted whereby engine drivers are warned of an obstruction. 
A series of wires on telegraph poles is carried along the side of the 
railway adjoining the cutting, and connected with a signal on 
the railway which normally stands at " clear/* and in the event 
of the wires being broken by falling rock the signal at once rises to 
" danger." 



CHAPTER VIII 

CONDITIONS AFFECTING THE COST OF EARTHWORK 

IN Chapter I reference was made to tlie various matters to 
be considered when preparing the estimate of cost of an earth- 
work undertaking. It is now proposed to discuss in some detail 
the points which affect the actual expenditure in the practical 
work involved. These vary very considerably under different con- 
ditions ; but, briefly stated, they are : 

(1) The cost of labour. 

(2) The character of the materials to be excavated. 

(3) The facilities for removal of the excavations or convenience 

in obtaining the embanking material. 

(4) The prevailing weather conditions when the work is in progress 

and the time within which the work is to be executed. 

It may appear superfluous to state that the financial success of 
an earthwork undertaking very largely depends upon the efficiency 
of the control of the operations. So much, however, attaches to 
the management that it is necessary to emphasize this point. A 
thorough knowledge of how to make the very most out of a job 
can only be obtained by a close acquaintance with constructional 
work and this, along with the qualification of handling men and 
a quick and clear appreciation of the difficulties and emergencies 
attendant on such work, combine to form the superintendence which 
is essential for obtaining the best results. 

The cost of the work can very materially be reduced by having 
skilful, resourceful, and experienced men in charge. These remarks 
apply equally to the manager, foremen, and gangers in charge of 
the various squads of men distributed over the work. This is 
specially necessary in the construction of earthwork on which 
the men engaged are for the most part drawn from unskilled 
labour. 

134 



CONDITIONS AFFECTING THE COST 135 

When large numbers of men are engaged and are exposed to 
changeable weather, working frequently under most adverse con- 
ditions, the proper housing of them is an important consideration. 
Attention to their personal comforts will more than anything else 
create a good feeling, with correspondingly satisfactory results in 
the execution of the work. 

With a view to expediting the output from cuttings or the form- 
ing of embankments the Contractor may find it convenient to 
encourage the " gangers " who are in charge by paying them 
bonuses on results, after the number of wagons or cubic yards 
handled per diem exceeds a certain number. A similar object is 
attained by sub-letting the labour to the " ganger/' thus giving 
him a financial interest, however small, in the work. 

The contractor will find it to his advantage to have a systematic 
cost made every week or fortnight throughout the whole course 
of the operations, from which he will see whether the work is being 
profitably and economically executed. 

For this purpose he should have a costing Engineer, whose duties 
will be to calculate the quantities of the several items of work and 
collaborate with the timekeeper at the works, who should furnish 
him with the actual expenditure under each heading of cost. 

The diagram (Fig, 72) shows a form of cost statement suitable 
for the several works met with in an earthwork contract. 

In the case of the cuttings the statement will show the total 
quantity of material removed over a period of a week or fortnight, 
together with the actual expenditure for that period and the cost 
per cubic yard can thereby be obtained. 

Alongside of this cost there is shown the rate in the Contract 
Schedule, and the Contractor can see at a glance whether the work 
is being carried out at a profit or loss. 

The statement also shows separately the cost of the labour, 
plant, and stores per cubic yard, and from this information he 
should be able to locate any excess expenditure. 

Under the heading of " Plant/' the amount in respect of wagons, 
cranes, locomotive engines, steam diggers, and other heavy plant 
should be computed on the basis of the cost being distributed 
uniformly over a period. Two years might be taken, and on this 
basis, if a locomotive should cost 2000, the cost each fortnight 
exclusive of coal and other stores would amount to 38 9s. 3d. 



136 EARTHWORK IN RAILWAY ENGINEERING 







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CONDITIONS AFFECTING THE COST 



137 



The statement will also show the actual cost of concrete, 
masonry, and brickwork in building culverts, etc., and as in the 
sase of cuttings any excess expenditure should be investigated. 

The importance of having these costs prepared will be more 
fully appreciated when reference is made to Fig. 73, which gives 



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Hard dotted tine re presents cost per oub/e yard. 

Hard full l!n& represents output in cubic yards, each fortnight, 

Fia. 74, Diagram of cost and output of railway cutting* 



particulars obtained from the cost statements of output and rela- 
tive cost of a cutting including disposal in an embankment, eztend- 
ing continuously over a period of twelve months. TJie material 
in the cutting consisted of sand, or sand and gravel, and was 
deposited in embankment at an average distance of about a nolle 
from the cutting. 
Fig. 74 gives the same informatioB diagramatically^ and clearly 



138 EARTHWORK IN RAILWAY ENGINEERING 

shows how, with a large output, the cost per cubic yard is very 
much less than what it is when the output is low. 

The two best months' work was in March and April, the average 
output during that period being 615 cubic yards per day at an 
average cost of 7 -3d. per cubic yard. The average output over 
the whole year was 350 cubic yards per day at an average cost 
of 10-2d. per cubic yard. These costs include depositing in 
embankment. The work referred to was executed previous to the 
outbreak of the European War in 1914, when navvies' wages 
averaged about 5d. per hour, and consequently do not represent 
the cost of the work at the present time. 

A saving of |d. per cubic yard in the cost of excavations spread 
over 1,000,000 cubic yards represents over 2000, and this will 
repay the Contractor the additional expenditure incurred in having 
the costs made. In work of this description constant vigilance is 
necessary to ensure the most rigid economy. 

The Engineer, for his own information and for that of the pro- 
moters, should be fully informed as to the progress and cost of the 
works as the operations proceed, and this can best be seen in a 
diagram. 

Information of this description shown on a diagram indicates 
at a glance whether the operations are being satisfactorily executed, 
both as regards cost and progress. 

As regards the cost of labour, the fluctuations of the labour 
market may largely affect the cost of the work, a small increase or 
decrease of the rate of wages being sufficient to very materially 
influence the total value. If wages are low when the work is 
being tendered for, the Contractor, keeping in view a probable 
rise during execution of the works, may found his estimate on the 
basis of a higher rate, but by so doing he may reduce his chance 
of obtaining the contract. This difference will, of course, be more 
apparent in work on which the greater part is executed by hand 
labour rather than on that where steam diggers or other heavy 
plant are used and where the quantity of material handled is 
considerably greater per man employed during a given time. 

In connection with the character of the materials to be excavated, 
while the classification of " soft " .and " rock " may be sufficient 
on which to prepare a Contract Tender, these two designations very 
inadequately describe the various kinds of material that may be 



CONDITIONS AFFECTING THE COST 139 

met with, and in many cases misrepresent the characteristics of 
them so far as their removal from a cutting or placing in an embank- 
ment is concerned. A dry sand cutting is the simplest and least 
expensive to excavate, but, if there should be water in the sand, 
the removal of it may be equally as costly and much more 
troublesome to deal with than solid rock. 

A tough boulder clay is the most difficult of " soft " materials to 
excavate, but certain clays or clay with sand are very troublesome 
if water is present in sufficient quantity to convert it into " slurry." 

The cost of the work is thus largely dependent on the quantity 
of water met with and the effect of water on the materials to be 
excavated. 

If clean, sharp sand, gravel, or solid rock is met with in the 
cuttings, it will have a commercial value in so far that sand and 
gravel can be used for concrete, freestone, or granite for building 
purposes, and freestone or whinstone for road making and pitching 
slopes of streamy and water-courses. 

In the case of excavations in solid rock, if it is such that it can be 
put to any of the uses referred to it will generally be advantageous. 
The time under which the work is to be executed may, however, 
necessitate its removal by the usual methods of blasting instead 
of by quarrying as would otherwise be done. A good rock cutting 
is a decided asset, and the cost of excavation should be credited 
with its value, provided it can be used. If there should be a large 
quantity of rock to excavate, the removal of it may be the key 
to the completion of the work, and it may consequently be 
necessary to expedite operations by carrying them oa at several 
points by sinking trenches and driving headings at considerably 
greater outlay than would be incurred if the work can be pro- 
ceeded with from open ends. 

It may be a convenience to lay an overland service route clear of 
the cutting to link up the lines of communication between the works 
on one side with the works on the other side, and thereby give 
greater freedom in excavating the rock cutting. 

In both soft and rock cutting, where it is not possible to have 
free drainage from the working face, the unit price will be increased 
by the expense of the pumping necessary to keep the excavations 
free from water. 

Considerable importance attaches to the facilities for removal 



140 EARTHWORK IN RAILWAY ENGINEERING 

of the excavations from a cutting. It is in this connection that the 
work of a canal, dock, or other open excavation is so materially 
different from the confined space generally anticipated in a stretch 
of railway, road, or similar work. 

As has already been pointed out, it is necessary, in order to obtain 
sufficient width to excavate a cutting for a single line of railway by 
means of a steam digger, to carry on the operations at a level of 
about 4 ft. above the level of formation. The bottom portion 
has thus to be taken out by hand at a greater unit cost. In a 
double line of railway work can be carried on at formation level 
with better facilities for bringing forward and removing the muck 
wagons, and, if there is greater width, as in the case of a canal, 
the accommodation for wagons will be still better, with consequent 
less delay or stoppage of the operations. When, as is sometimes done 
in canal excavations, the material is deposited on land immediately 
adjoining the cutting, any delay will be due to a break-down of the 
digger or excavator, and any cessation of operations will be reduced 
to a minimum, and the unit cost will also be a minimum. 

As already stated, the cost of the work is largely dependent on 
the relative positions of the cuttings and embankments and the 
length of the " lead ** from the cutting to the embankment or 
other place of deposit. 

It is, of course, a convenience if the material can be run down 
grade to embankment. 

In the event of it being necessary to run material to spoil embank- 
ment the cost will be increased by the rental of the land on which the 
spoil embankment is situated and also the restoration of the surface. 

The conditions of the weather and the season of the year during 
which the work is being carried out sometimes very seriously affect 
the cost. It has already been suggested that practical operations 
should be commenced during the early springtime, so that full 
advantage may be had of the more favourable weather and long 
day of the summer season. In work extending over a period of 
years every effort should be made to get as much done as possible 
in good weather, and during unfavourable weather conditions 
operations should if possible be curtailed or temporarily suspended. 

When work is carried on in wet weather not only is the cost of 
the excavations increased, but the material when put into embank- 
ment, being in a sodden condition, may cause aeriou^ dipping at 



CONDITION'S AFFECTING THE COST 141 

a subsequent date, necessitating considerable expense in repairs. 
While the men usually employed are only paid during the time 
they are actually engaged, there are " oncost " charges for 
managers, engineers, foremen, etc*, as well as the interest and 
depreciation in value of the plant in use, to be met whether the 
work is being carried on or not, but it is better to stop operations 
for a time if the circumstances will permit. 

Under certain conditions the actual cost per cubic yard of 
a cutting taken out by a steam digger may not be less than that 
excavated by hand, but the larger output and the ensuring of the 
work being executed in favourable weather may justify the use 
of the digger. 

The effect of weather conditions on the cost of the work and the 
advantage to be gained by making the most of the good weather 
both as regards the reduced cost and the larger output has already 
been referred to. 

Considerable expense is sometimes incurred in maintaining 
service lines of railway when crossing soft ground, by having to 
make up subsidences with ashes or otherwise* 

The time within which the work is to be executed may require 
that operations be unduly pushed, but before tendering a Con- 
tractor should satisfy himself that the time allowed under his 
Contract is sufficient to enable him to execute the work in a manner 
corresponding with the amount which he has stated in his Tender. 
The time allowance may be altogether inadequate no matter 
what the mode of procedure may be, and not infrequently Engineers 
make the mistake of not giving this point sufficient consideration. 
As a common example, the greater part of the excavation of a rail- 
way may be confined to one cutting, and the more economical 
method might be to take it out by means of one or two steam 
diggers, working teom the lower end of the cutting ; but, in order to 
complete the work within the Contract Time, it may be necessary 
to proceed with the excavations from both ends simultaneously,, 
and the probability is that at some points it may be necessary to 
exicavate against the gradient, necessitating pumping and addi- 
tional eteam power at greater cost. If the same quantity of 
material were distributed over two or three cuttings where each 
could be working independently of the other, the cost would be 
much less and the work executed in a shorter time. 



CHAPTER IX 
SPECIFICATION 

THE execution of all engineering works of importance is carried out 
under Contract. The Contract Specification consists of " General 
Glauses " for the protection of the rights of both parties to the 
Contract. These are, for the most part, of a legal character, and 
there are in addition " Works Clauses/' which are descriptive of 
the class of work and the manner in which the Engineer wishes 
it carried out. 

The Specification is framed by the Engineer and forms one of 
the Contract documents signed by the Contractor, and is binding 
on him for the due fulfilment of the Contract, 

In th@ preparation of the Specification the Engineer should be 
careful to ensure that what he wants is clearly brought out, tod 
that he is neither asking for more than he expects to get, nor taut 
than is essential for what he will afterwards insist on having. The 
language should be perfectly clear and of the simplest description, 
having only one interpretation, so that there may be no subsequent 
ambiguity as to the meaning attached thereto. The Engineer 
must himself understand his Specification as otherwise he cannot 
complain if the Contractor fails to understand it. 

In no constructional work is a Specification more necessary than 
in a Contract involving the execution of earthwork, and there is 
probably no other class of work where the Specification is more 
frequently departed from. There has probably been more con- 
troversy over questions of earthwork than any other operations 
which fall to be dealt with by an Engineer. 

The essential points for the " Works Clauses " of an earthwork 
Specification have already been revealed in describing the various 
constructive operations, and in the present chapter it is proposed 
only to refer briefly to a few of lie points of difference which 
frequently arise in carrying out Contract work. 

14.9 



Prices are cut so keen in making up a Schedule that it is not to 
be wondered at that a Contractor should claim to be paid for the 
slightest departure from the terms of the Contract, and at times 
play on the sympathies of the Engineer to get something more 
than a rigid interpretation of the Specification allowed. 

A frequent cause of difference has reference to the classification 
of excavations. This matter has already been referred to under the 
heading, " Investigations as to Strata," at page 17, and " Cost of 
Earthwork," at page 139. 

It is usual to have earthwork material classified in a Contract 
Schedule with the two descriptions, " soft " and " rock." A common 
form of Specification reads, "All material other than solid rock 
will be paid for as ordinary e excavation/ " and, " Nothing will be 
paid for as rock except solid sandstone, solid limestone, or solid 
whinstone." It might at first sight seem better to have a middle 
classification of " soft rock " in cases where large quantities of 
material have to be removed, this term to include such material 
as fireclay or other shaley clay, hard boulder clay or close-bound 
gravel, which are only capable of removal by means of a pick and 
which not infrequently requires to be loosened by blasting. Materials 
of this description are more difficult to remove than sand, loose 
gravel, clay, or earthy material, and it is the classification of 
materials of this description that raises the point of difference, 

Some Engineers ask Contractors to give an overhead rate to 
cover all classes of material which he may meet with, and, while 
this may get over the difficulty of classification, it is better that the 
Engineer in calculating his quantities should have a distinction 
between " soft" and "rock," and the writer is of opinion that 
no advantage is gained by having an intermediate class. 

Part of the soft material may be very difficult to excavate, or it 
may contain a large volume of water, which makes it much 
more costly to remove than if the cutting was dry ; but the Con- 
tractor should carefully consider these matters with the informa- 
tion obtained as to strata supplemented by minute investigations 
on the ground and any additional particulars he may obtain as to 
the probable quantity of water likely to be met with, when carrying 
out the work. He must also consider what means will require 
to be taken to intercept the water and direct it clear of the opera- 
tions, and price bis Contract Schedule accordingly. 



144 EARTHWORK IN RAILWAY ENGINEERING 

This raises the question of the accuracy of the preliminary 
investigations which has already been fully dealt with in Chap- 
ter II. The quantities of material separated into " soft " and 
" rock/' stated in the Contract Schedule, are prepared from this 
preliminary information, and if those quantities have been imper- 
fectly estimated, or if any of the material to be excavated has been 
wrongly described, the cost of the work may be largely exceeded 
and the Contract time for completion may be inadequate. 

As already stated, it is customary for the Engineer to have 
trial bores put down on the line of the railway or site of the works, 
and the Contractor will have the benefit of the information so 
obtained. The journal of these bores should not, however, form 
part of the Contract Documents, and the Contractor will require 
to take the risk of the materials in the excavations turning out 
different from what he may have expected. This matter is also 
referred to in Chapter IV, page 47. 

In connection with bridges, culverts, etc., it is important that 
these be detailed as fully as possible in the Contract Schedule. All 
culverts require to be constructed previous to the railway embank- 
ment under which they are carried being formed and the greater 
number of bridges, both over and under the railway, will also require 
to be constructed before the railway is formed up to them. Conse- 
quently, the materials for these works may require to be taken 
over fields and inferior roads at greater cost than would be the 
case if the points on the line where these special works are being 
constructed were more easily accessible- The Contractor may have 
a " flat " rate for masonry, concrete, etc,, no matter where the 
works are to be situated on the contract, but it is better that he 
should have the opportunity of pricing the items for each work 
separately, and he cannot afterwards have any grounds for claim 
on account of the inaccessibility. * 

Any departure from the original schedule will, in all probability-, 
add to the cost of the work, and that in a greater proportion than 
the increased quantities represent. 

Questions relating to damage by water not having been properly 
intercepted alongside of cuttings and embankmemts, and to the 
operations not having been executed in such a maixaer as to pre- 
vent the occurrence of slips, frequently arise. It is usual to a*k 
& Contractor to state a sum for dealing with alip6 which aiwa m 



SPECIFICATION 145 

over and above payment for tlie construction of such intercepting 
catch- water and slope drains as the Engineer considers are essential 
for the construction of the works. The sum stated by the Con- 
tractor in his Schedule may be altogether inadequate to cover the 
cost of slips that will occur under the best of management, but 
the Contractor is liable in any expense thereby incurred. In 
carrying on his operations the Contractor will require to execute 
such temporary drainage and other contingent works as are neces- 
sary in his own interests, but if the operations are under proper 
superintendence, the risk of damage by reason of water will be very 
largely reduced. 

The necessity for executing the drainage work of the adjoining 
lands previous to the cuttings and embankments being commenced, 
and the importance of timeously dealing with water which appears 
in a cutting, have already been referred to in Chapter VI. 

It is usual to stipulate in the Specification a date before which 
the works are to be completed, and, in fixing the Contract Time, 
the Engineer should put himself in the position of the Contractor 
and consider how the work is to be done within the time which he 
proposes to stipulate. The value of the work is not necessarily 
the measure of the time for completion, neither is the total 
volume of material to be excavated. There may be 250,000 
cubic yards of excavation to remove, and if this quantity is in 
several cuttings and can be proceeded with simultaneously at 
various points the work will be more speedily executed than if 
the whole of the material is to be removed from om working face. 
The removal of the excavations from a cutting may depend on the 
construction of a tunnel, viaduct, bridge, or other work, and this 
should be kept in view in fixing the Contract time. As has already 
been stated, the time of the year in which the work IB executed 
will also largely affect the time taken to execute. 

Endeavour should be made, as far as possible, to avoid time 
account work, and any eottea woik should, wherever possible, 
be paid for at Schedule rates, or at rates proportionate to the 
Schedule rates for similar work. There is always a temptation on 
the part of the OontiB&ctor to unduly extend work when he knows 
that he will be paid for it by " time aad lime,'* 

The importance of employing experienced mean who are akplled 
m. this paxtieillar class of work has already been refcced to, and, 

3B.BJL L 



146 EARTHWORK IN RAILWAY ENGINEERING 

in many cases, a Contractor loses by not kaving the best of men to 
supervise his operations, and this is very frequently the cause of 
difference between the Engineer and the Contractor. If he should 
not have the works properly managed, the most successful methods 
will not be adopted, or by adopting particular methods he may 
be compelled to execute certain parts of the work in winter or 
during adverse weather conditions, and consequently the works 
are uneconomically carried out and at excessive cost. 

*The Contractor requires to have sufficient capital or have the 
necessary financial support to ensure that the works will not 
suffer for want of the most suitable plant. It is usual to specify- 
that " the -Company (or Corporation) do not bind themselves to 
accept the lowest or any Tender. 3 ' In advising his clients the 
Engineer should be satisfied that the Contractor whose Tender he 
recommends should be accepted is not only financially sound but 
that he is thoroughly capable of handling the Contract. For an 
earthwork contract, probably more than in any other engineering 
undertaking, the successful Contractor should be a specialist in 
this class of work. He may have sufficient capital or financial sup- 
port, but if he is not accustomed to the work he is not a success and 
the result reacts both on the Contractor and on the promoters for 
whom the work is being executed. If, on the other hand, he knows 
his work but lacks the capital, he is hampered through not being 
able to employ the most suitable plant. 

The contract will probably include steelwork for bridges, and 
the Engineer will require to be satisfied that it can be properly 
executed and timeously supplied. If the steelwork is not erected 
at the time when it is wanted, the Contractor may be put to the 
expense of providing temporary trestle bridges or constructing 
other temporary works at considerable expense. 

Before recommending a particular Tender, the Engineer should 
be satisfied that the Contractor can execute the work for the 
amount of his Tender. If it is quite apparent that the Contractor 
is going to lose by the contract, it ia better that the promoters 
should not give him the work to execute, as the work will most 
probably cost the promoters more in the end than they would other- 
wise have paid if the Schedule had been correctly priced. 

The Contract will include for maintaining the whole works lor a 
period after completion, generally twelve months, aaad the 



SPECIFICATION 147 

Schedule should have an item for maintenance for that period. The 
Contractor may not enter a price opposite this item, or the sum 
which he states may be inadequate, in which case it is assumed 
that the other items in his Schedule either in whole or in part allow 
for the cost of maintenance. In the case of the greater number of 
engineering works, the cost of maintenance may be small, but 
in the case of the earthwork of a railway the cost of proper main- 
tenance may be a fairly large sum. This maintenance includes the 
repairing of slips and soiling of slopes which may have been damaged 
by weather, the cleaning of ditches, and the bringing to proper 
level any embankments which may have subsided, and the leaving 
of the work in an entirely finished condition. The cost of main- 
tenance is largely influenced by the manner in which the several 
works have been executed. This matter has already been referred 
to in Chapter VII. 

The points above referred to are sufficient to indicate the diffi- 
culties attached to the Engineer's duties where he wishes to be 
absolutely fair to the Contractor, while at the same time jealously 
guarding the interests of his clients who have to pay for the work. 



INDEX 



of repose of various materials, 
100 
Arch culverts under railway, 23 

B 

BI/ASTIKG for steam digger in hard 
cutting, 53, 117 

rock in cuttings, 93 
Bog or moss land, 67-69 
Bonuses to navvy " ganger 8," 135 
Bores, additional, taken by contractors, 

47, 144 
Boring, chisel, 11-14 

diamond, 14-16 

importance of, 10 

necessity for, 17 

rate of progress, 17 

wash-out "drills," 17 ^ 
Boundary fences, determined from 
cross sections, 40 

determined by levelling at site, 41 
Box drains of timber, 22 
British permanent way, 128 
Built stone drains, 23 



C 

of areas of cross section, 



42 



Capital required by contractor, 146 
Character of materials and cost, 6, 138, 

139 
Characteristics of various materials, 

99, 100 

Chisel boring, 11-14 
Classification of materials, 138, 1S9, 143 
Clay slopes, action of rain storms on, 

107 

Consideration of railway project, 2 
Contract, cross sections, 40 

drawings, 37 

general plan, $7 

longitudinal section, 39 

schedule, $6, 144 

specification, 36 

Aim of compilation, 145 



Contract, commencement of, 43, 140 

Contractor's risks, 47 

Conveyance of excavations, 93-98 

Coolie or black labour, 72, 73 

Cost of earthwork, facilities for work- 

ing, 139, 140 

character of materials, 6, 138, 139 
price of labour, 138 
relative position of cuttings and 

embankments, 45 
time allowed for execution, 141, 145 
weather conditions, 141 
Cost of plant, 135 
Cost of single and double line of rail- 

way, 2-4 

Cost statement form, 135 
Cost system, 135 
Cost of work over extended period, 136 

diagram of, 137 

Culverts, built stone drains, 23 
capacity, 19, 20 
constructed in advance of embank- 

ments, 50 
design of, 21-23 
design of ends, 27, 28 
fire-clay pipe drains, 22 
formula for discharge from catch- 

meat areas, 19 
maintenance, 133 
on side-lying ground, 24-26 
on soft ground, 26 
riveted, malleable iron or steel 

tubes, 24 
steel beams and concrete covering, 

24, 

timber box drains, 22 
Cuttings, objection to cutting away toe 

of slope, 54 

objection to long gullets, 54 
procedure in construction, 61 
removal of cuttings by hand, 52 
removal of cuttings by steam 
digger, 53 



B 



in 



for flood 



wa-tjer, 



150 



INDEX 



Deviation, local, with a view to less 
costly culverts or water-courses, 
18 

Diamond boring, 14-16 
Discharge from catchment areas, 

formula, 19 
Drainage, interception of, necessity for, 

145 

Bog or moss land, 67-69 
British permanent way, 128 
executed before other works, 18, 49 
Pennsylvania Railroad permanent 

way, 132 

permanent way, 129 
site of embankments, 121 
slope drains in cuttings, 105, 106 
thorough, a means to prevent 

slips, 111 

works periodically inspected, 127 
Drains, slope drams in cuttings, 105, 106 
large slope drains in cuttings, 108 
Dwarf walls in soft cuttings, 108, 109 

E 

EAR.THWOBE: constructed by coolie or 

black labour, 72, 73 
exceptionally heavy, 75, 76 
maintenance, 127 
risks of delay in execution, 58 
Economics in construction, 4 
Efficiency of control of operations, 134 
Embankments, construction of high, 

118 
Embankments, less liable to snow 

blocks than cuttings, 6 
procedure in forming embank- 
ments, 56, 59 
in soft ground, 121 
in unstable side-lying ground, 121 
Engineer's report, 1 
Estimates, preliminary, 2, 8 
Excavated material, disposal of, 54 

F 

FACILITIES for removal and cost of 
earthwork, 139, 140 

Jftre-clay pipe drains, 22 

Mood water, openings through embank- 
ments, 20 

Depressions in railway embank- 
ment, 21 

Formula for discharge from catchment 
areas, 19 

G 
GRAVEL, close bound, 10 

Gullets, objection to long gullets,, 54 



HAND-HAMMER machine rock drill, 9L 
92 

Hydraulic method of forming embank- 
ments, 74 



machine rock drill, 



89-91 



LABOUR, price of labour and cost of 

work, 138 
Land, extent of land required, 7 

setting out, 44 
" Lead " down gradient when possible, 

140 

Location of railway, 2 
Loose rock cuttings, slips, 109, 110 
Lubecker land dredger, 87 

M 

MAINTENANCE, advantage of greater 

width in cuttings, 4 
culverts, 133 
earthwork, 127 
permanent way, 127-129 
slopes, 132 
work, contract, 146, 147 



O 

channels or pipes along forma- 
tion, 131 



PENNSYLVANIA Eailroad, drainage, 132 

Permanent Way, maintenance, 127- 

129 

drainage, 129 
section of British, 128 
section of Pennsylvania Bailroad. 
132 

Pipe drains along foot of slopes of 
cuttings, 130, 131 

Plan, contract, 37 

Plant, necessity for sufficient plant, 146 
hand labour, 77, 78 
Lubecker land dredger, 87 
rock drilling by hand-tools, 89 
hand-hammer machine drill, 01, 92 
IngersoU-Rand machine drill, 

89-91 

Euston steam cran navvy, 79-8S 
Ruston steam shovel, 85, $6 
Wilson steam crane navvy, 84* 85 

" Plug and feather*" IB. 



INDEX 



151 



Preliminary estimate, 2, 8 

investigations, 144 

section, 7 

Procedure in constructing cuttings, 51, 
55, 56 

embankments, 56, 59 

excavating rock cutting, 62 

Q 

QUANTITIES, importance of accuracy, 10 

R 

RAILWAY, cost of single and double 

line, 2, 3, 4 

cuttings, examples, 63-67 
local deviation and economy in 

culverts, 18 
maintenance, 4 
service, 48, 139 
setting out, 44 
widening, 70-72 
Bock cuttings, face wall in soft cuttings, 

110 

excavation, 62 
retaining wall in soft cuttings, 

111 
signal to indicate fall of rock, 

133 

use of materials, 139 
Rock drilling by hand, 89 

by hand-hammer machine, 91, 92 
by Ingersoll-Rand machine, 89-91 
Rock excavation, blasting, 93 

" plug and feather " method, 78 
Ruston steam crane navvy, 79-83 
shovel, 85, 86 

S 

ScHBDtrLB, contract, 36 
Scheme of operations, 47 
Scraper machines, drag and wheel, 73, 

96-98 

Section, contract, 39 
prettminary, 7 
working longitudinal, 46 
Service railway, 48, 139 
Setting out railway, 44 
Setting out land and works, 44 
Side chawotels or pipfc drains along foot 

of slopes of cuttings, 130 
$Mte-lyig ground, railway formed on, 5 
cutting trenches on. 119 
embankments on unstable, 121 
slips in embankments on, 122 
waterlogged, 12S, 124 

fmo for tBow drifts, 133 



Slips in cuttings, 101 

in cuttings requiring special treat- 
ment, 113-115 
in cuttings of large dimensions, 112, 

113 

in cuttings in loose rock, 109, 110 
in cuttings of small dimensions, 

111, 112 

in embankments, 116 
in embankments due to water- 
logged material, 125 
in embankments due to character 

of materials, 124, 125 
in embankments, due to character 

of strata under site, 120 
in embankments on side-lying 

ground, 122 
through drainage, 111 
Slope drains in cuttings, 105, 106 

large, 108 

Slope of various materials, 9 
Slopes of cuttings and embankments, 

50, 118 
Snow drifts, 133 

sheds, 133 

Soft material containing water, 143 
Soiling and sowing slopes, 107, 108, 119, 

132 

Soil-stripping surface, 51, 119 
Specification, cause of differences, 
classification of excavations, 143 
contract, 36 

contract should be explicit, 142 
Spoil bank, site of, 5 
Springs under site of embankments, 122 
Steam crane navvy, Ruston, 79-83 

Wilson, 84, 85 
Steam digger, large output, 141 

width of cutting required, 54 
Steam shovel, Ruston, 85, 86 
Stone drains under railway, 22 
Strata, character affects cost, 6 

character affects extent f land 

lequircd, 7 

investigation as to, 9 
necessity for fullest information, 

m 9, 10 

Subsidence in embankments, allowance 

for, 61 
Syphon pipe under railway, 83 



TIMBBB box drains, 22 
Time account work, 14S 
Tim of completion, 141 
Up wagons, iron, 94 

wood, 95, 96 



152 



INDEX 



Trenches, cutting, in Side-lying ground, 

119 
Trestles, timber, 74 

carrying water- course, 33, 34 
Trial pits, 9, 16 

Turfing foot of slopes of cuttings, 119, 
131 

W 

WAGONS, iron and wood, 94-96 
side-tip versus end-tip, 60 

Walls, drystone dwarf, 108> 109 
face, 110 
retaining. 111 

Wash-out "drill," 17 

Water, damage by, in cuttings, 102, 103 
action on clay slopes, 107 
damage through, improper inter- 
ception, 144 
interception of, in strata, 104 



Water, large volumes of, in cutting, 115, 

116 

openings through embankments, 20 
under site of embankments, 123, 

124 
Water-courses, combined in one eulvert, 

29 
and road accommodated on one 

bridge, 33 

carried by a syphon, 33 
carried down slope of cutting, 34 
carried in open conduit, 33 
carried on a road bridge, 33 
carried on trestles, 33, 34 
diversion along contour, 30 
road and stream through same 

opening, 33 

Weather and co,st of earthwork, 141 
Widening of existing railways, 70-72 
Wilson steam crane nawy, 84, 85 



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William 



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their complete stock or at 

short notice, 

Any Technical or 

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In addition to publishing a very large 
and varied number of SCIENTIFIC AND 
ENGINEERING BOOKS, D. Van Nostrand 
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