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Full text of "The history and methods of electrification of the Pennsylvania Railroad between Baltimore and Washington, D.C. / by Charles Herbert Ludwig."

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Charles Herbert J-udwig 


DECEMfiEH 1>, 1934 

1 - 


The author haa attempted in this thesis to present 
a blrdseye viejr of the PennsylTania Hailroad'a electrif- 
ioation program from Baltimore to Washington D. C. All 
phages of the work are discussed in general, with just 
enough detail to bring out the engineering technique in- 

The entire New York to Washington electrification 
was discussed in dealing with the historical and flnanoial 
sides of the project because of the information obtainable, 
and also in order to give a clearer presentation. The 
figures appearing in the financial section are only approx- 
imated or estimated values as they represent overall costs 
which are not readily obtainable at this early date. 

To make the thesis more interesting, pictures and 
illustrations were inserted wherever possible, and an ap- 
pendix was added at the end to include Interesting material 
not presented in the main body of the thesis. 

- -2 - 


HISiX)iiY AiljD JJJiViDi^PMjJJi 


Changes Neoesaary at Washington. D. C. 
Changes Heoessary at Baltimore. 
Headway Changes Along the Line. 
Changes In Signaling System. 



Power Supply. 
Power Distribution. 
Power Supervision. 
Power Seotlonallzlng. 


The Erection of Catenary Supporting Sturotures. 
The Ereotion of the Catenary. 



The Type How In Use. 
Hew Type. 


Lightning Protection. 


New Calculating luaohine»; 





One of the outstanding faotore in the unification and 
development of the United States into a great Industrial, oommer- 
clal, and agricultural state ia the erolution of the railroad. It 
has been possible, through the medium of the railroad with Its 
intricate maze of rails that spread throughout the entire United 
States, to unite the interest of the great mass of people by 
drawing them into closer relationship. 

The Pennsylvania liallroad represents one of the large 
•astern systems which has always endeavored to keep abreaat the 
demands made upon it by the growth of the industries it serves. 
The latest step taken by this railroad Is the electrification 
and improvement of its lines so that when finished there will be 
a completely equipped electrified service beginning at Hell Gate 
Bridge, New York City, where connection is made with the New 
England electrified railroads, to Washington, D. C. At this 
writing 80^ of the work has been completed, and work is being 
concetrated on the section between Baltimore and Washington, D. C, 
and it is the construction of this section that will be presented 
in this treatise. 

i'irat, however it will be well to briefly review the 
electrification program in its entirety. 

In 1910 the Pennsylvania iJallroad electrified its line 
from Sunny side Yard, Long Island, through the New York Terminal 
in New York City to a point near Newark, New Jersey. Suburban 
Transportation by means of multiple -unit cars was initiated be- 


tween Philadelphia and Paoli in 1915' '^his waa extended to 
Wilmington in 1928. 

The present electrification program^ including both 
passenger and freight aerviee, hetveen Sew York and Washington, 
D. C. was authorized in 1928 hy the Board of Directors, who 
stated that the chief advantages of electrification are that it 
makes possible the handling of a denser traffic over the same 
tracks, much larger trains can be operated and with greater flex- 
ibility in speed, and the 003 t of operation and maintenance will 
be reduoed. It will require approximately 816,000,000 kilowatt 
hours per year (1,094,000,000 hp. per year J to operate the total 
Pennsylvania a. c. traction territory^ when the eleotrif loatlon 
is complete ; this represents an average load of 125,000 hp. it 
will include 1,519 miles of track, 21 step-down aubatationa, and 
seven supply stations. Ihe total substation capacity of the JJew 
York-Washington section Trill be 1,196,500 Kva. The program also 
includes new locomotives, cars, and new terminal facilities in 
Hewark, Philadelphia, and Baltimore. The entire program re- 
presents a cost of over ^265,000,000. 



The Pennsylvania iiallroad first began work on the New 
York to Washington Electrification and Improvement program in 
1929. Jhe original construction schedule, formulated in I928, 
called for financing the work largely out of earnings. Under that 
schedule the work was to have been spread out over a period of 

- 5 - 

6-8 years. However, adverse traffic oonditiona in 1930 re- 
atrioted earnings, and in 1931 the borrowed )77,000,000, 
The work was pushed vigorously in 1931f in antloipation of com- 
pleting by 1933 • Iii January 1932 work: was stopped through laok 
of funds. Ihia waa brought about due to the inability of the 
Ballroad to market reasonable amounts of securities at fair or 
real values, or to secure relief through loans from banks. In 
Other' words old man depression was at work. Ihere was only one 
other source to obtain money and that was through the He con- 
struction Finance Corporation. Consequently, in Haroh 1932 the 
Pennsylvania iiailroad applied for a loan of ^55,000,000 for s 
period of three years. In the meantime, however, the -dailroad 
was able to sell some of its securities, and as a result the 
amount aaked for was reduced to ^27, 500,000. The application was 
approved iiay I6, 1932. 

The status of the electrif ioation and improvement pro- 
gram in January 1952 was as follows: 


Jan.l Proposed Additional 

1932 19^2 to complete 

Electrification, Hew York to 

Washington. ^26,257.327 14.7.000,000 ^37,185,924 
Hewarlt imiDrovements 1,497, 076 2,000,000 16,502,124 
Philadelphia improvements 74,302,046 9,822,000 24,168,605 
Baltimore improvements 5,403,838 1,500,000 19,095,162 
Miscellaneous IJJ 7,054,000 400,000 

'^°^^^ - 68,176,000 97,552,813 

(1) Sot ascertained 

With new financial support the work was continued. 

On Beoember 29, 1933 the itailroad borrowed $77, 000, 000 

from the ^tolio Works Administration of which 145,000,000 will go 

- 6 - 

to the completion of t.-ie electrif loation between New York 
and //asliington, and 152,000,000 for the nev? freight cars, 
looOfflOtiTes, and rails. 

The projeot is particularly adopted to the P. W, A. 
employment program in that the federal money will go pract- 
ically 100;^ for wages and materials, and it will he of direct 
widespread oeneflt in aiding heavy industries and capital goods 
production. This is verified by the fact that the entire pro- 
gram requires approximately 45,000,000 man hours of direct 
labor, and the total cost will be over ^255,000,000, At the 
present time 11,200 peoTle are employed on the project, and their 
monthly payroll runs over |l, 000, 000. 



The substitution of electric for steam power required 
numerous changes throughout the entire railroad system. Xhe 
moat imyortant which include rearrangements in terminal, road- 
way, and signaling sy interns are discussed in the following para- 

Changes llecessary at Washington, D.C. 

Approximately 1^5.500,000 ia being spent in the District 
of Columbia and vicinity on the electrification program. The pro- 
ject Inoludea the electrification of 19 tracks in Union Station, 
several engine terminals, the Virginia Avenue lunnel, a part of 
the Pirst street Tunnel, portions of the Potomac Freight Yard 

Union Station IVashington-Terminal 

Pennsylvania Station-Baltimore Terminal 

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near Alexandria, Va,, and the oonstruotion of several sub- 

The eleotrlf icatlon work In the District alone in- 
volves 80-iDile8 of track. Ihe railroad's two main line traoka 
entering Washington from the north will be electrified as far as 
New York Aveniie. From there 5 traoks will be electrified to the 
tower juat outside the Union Station. In the station itself, 
tracks 12 to 20, inclusive, on the upper level, and 20 to 29, In- 
olusive, on the lower level, will be prepared for electric oper- 
ations. Altogether approximately 59 miles of track will be eleo- 
trlf led on the railroad's main passenger lines to and through the 
Union 3a talon, and 40 miles of track on the Anacostia freight 

iTwo substations are being erected to regulate the flow 
of power to the trains, One, named "Capital", la located on 
3outh Capital at G Street, and the other named "Union," is just 
outside Union Station. 

Other features of the work will include the lowering of 
tracks on the Anacostia freight line at 10-11-12 th Streets, and 
on the passenger line under the B. & 0. Bridge at the Ivy City 
^glne Yard. About 48 feet of track in the i'irst Street i'unnel 
also will be lowered to provide greater clearance for the over- 
head feed wired. 

The signal and oommunioation system, including telephone, 
telegraph, and signal lines Is being completely rearranged. 

Ihe poles erected in the District will be J5 feet high 
and designed to conform to the recommendations of the National 
Capital Park and Planning Commission. 

Union Substation located just outside Union Station 
Washington, D.C. Power is received by underground 
cables from Capitol Substation at 11,000 volts. 


Close up view of circuit breakers at Union Substation, 

Close up view o^ ;— r circuit breaker with sides removed. 

Placing a bushing in one of the i+TOO Kva, 132/l2Kv, 68 ton 
transformers at Capitol Substation. 

Another view of the Capitol Substation showing the high voltage 
bus on top of the tower. 

Capitol Substation located at South Capitol and G streets V^'ashington, D.C. 
Note the motor operated, 152Kv., horngap switches mounted on the tops of 
the towers. 

Mr. Charles Bogan who is inspector and electrical engineer at the Capitol 
Substation graduated from U. of M, in the class of 1952. 

- 8 - 

When the work la oompleted, Pennsylvania offioiala 
olalm Washington will have the advantage of a terminal location 
on the most important and extensive atretch of electrified rail- 
road trackage in the world. 

Changes In Baltimore. 

The Pennsylvania la spending around 19,000,000 in and 
around Baltimore on the improvement program including road and 
tunnel electrification, tunnel construction and the building of 
a new pier at Canton. 

I>uring 1954 a total of approximately 14,500,000 will ba 
spent on the electrification of the main passenger and freight 
tracks through Baltimore, Including the old and new Union tunnels, 
the Baltimore and Potomac tunnel, and tracks at the Bay View yard. 

The right-of-way from Gwynor'a falls to ffllkens Avenue 
was widened from two to six tracks, and other tracks In that 
vicinity were lowered about 8 feet. 

Together with the city, the railroad is taking over four 
grade -'crossing elimination projects. Bridge railings are being 
screened to a height of Gt feet above the sidewalks.* 

i?he two tracks in the Old Union tunnel, which was built 
in 1875, will, be torn up and replaced with one track in the center 
30 that ample clearance for electric operation will be obtained. 

In order to eliminate a bottle -neck which long had hamp- 
ered the flow of trains thru the city, a new double track Union 
or -off man street tunnel is being constructed parallel to the 
the old Union tunnel. The difficulty results from the narrowing 

See Picture 

Preparing to construct a curtain wall on a bridge 
in Baltimore. 

- 9 - 

df the four track main line to tTO tracka through the olty, mak- 
ing it neoessary to hold up freight trains while passenger trains 
are aped through. She tunnel heads underground at Sreenmount 
Avenue and emerges 3»400 feet eastward at Bond 3 tree t. Ihirty- 
three feet wide, the tunnel will provide a clearance of eighteen 
feet over the tracks. The oonstruotion is being carried out in 
two atage3--an open out section of approximately 1,4^0 ft., and 
the remaining 2,000 feet built by underground boring or shield 
construction. When rooks are not encountered the tunnel progress- 
es about twelve feet per day; through rooky ground about seven 
feet per day. The use of large shields which are pushed forward 
into the earth by powerful hydraulic jacks is an unusual feature 
of the underground work. And advantage of this method lies In 
the fact that the tunnel structure is practically complete as soon 
as excavation is finished and no interval is necessary for the walla 
or roof to set or dry. The tunnel will be the largest of its kind 
in this aeotlon, 36 cubic yards of earth and rock being displaced 
by every lineal foot of tunnel as compared with 25 oubio yards by 
the Holland vehicular tunnels under the Hudson Hiver. 

The 8,000 foot Baltimore and Potomac tunnel is considered 
adequate for present requirements, although the railroad made 
plans several years ago for constructing a ne-v tunnel in that 
direction. The electrification of this tunnel will be carried on 
chiefly at night when the traffic is lightest. One of the first 
tasks in this tunnel will be the lowering of traoK.a to provide pro- 
per clearance. 

- 10 - 
Hoad'vay Changes Along the Line. 

One of the difficult road'vay prohlems of the eleotri- 
fioatioa was that of obtaining adequate overhead olearanoe for 
pantograioh operation^ for movement of high freight loads, and for 
the catenary and high tension line supporting structures, Ihia 
inTolTed the removal of existing pole lines oaiTying oommunioatlon 
signal control, and secondary power lines, and the placing of 
these circuits in underground duct systems or in aerial cables 
carried on separate poles. 

The duets were laid along the shoulder of the roadway. 
Most of the trenching was done by hand because of the character 
of the ground and the limited olearanoe a. All the duota were 
laid below the frost line and were pitched for drainage. The 
duct sections under traces were encased in. six inches of reen- 
foreed ooncreta. V?hen crossing street and waterway bridges the 
wires were encased in specially designed composite steel and 
concrete duct boxes, which were made to rest on the bridge abut- 
ments or piers. 

In some instances it was necessary to raise overhead 
bridges, lower traces, and build curtain walla on the bridge 
railings to shield the overhead wires by minimizing the tempt- 
ation to throw things over onto the railroad which might cause 
damage if it should come in contact with the trolley wire. 

The above operations were made more difficult by the 
fact that they had to be carried on while the railroad and other 
traffic was present. At the points where ohanges in fridges, 
roadway, etc., to provide clearance were necessary, the situation 

- 11 - 

presented was studied jointly by the operating, motive power, 

transportation, eleotrif ication, and maintenance of way depart- 
ments, and the clearance finally agreed upon was determined as 
the result of balancing the clearance requirements for eleotr- 
ioal and transportation purposes against the cost of obtaining 

Changes in Signaling System. 

-i-Tha change-over from steam to electric propulsion 
necessitated a complete reconstruction of the signaling system. 
The ways id e signals of the semaphore type on signal bridges were 
replaced with position-light signals * which are mounted on new 
bridges whioh form a part of the "H" catenary structure. At inter- 
lockings the signals are mounted on heavy anchor -type bridges 
which act as anchors for the trolley system. The signals were 
relocated to afford proper spacing for train speeds of 75 miles 
per hour with three-block indication. 

Continuous ooded cab-signaling was installed, and loco- 
motives were equipped with cab signaling indications which are, 
caution-slow speed, approach, approach-restricting, and clear. 

As tae propulsion current is 2 5-oycle, it was necessary 
to use a different frequency for the signal track oireuits to 
prevent any interference. Inerefore, luO-oycle current was 
adopted which necessitated an entirely new 100-oyole power system. 

An important feature of the signaling was the install- 
ation of Impedance bonds, the function of whioh is to terminate 
the 100 cycle track circuit at each signal location, but to con- 
tinue on to the next block the rail circuit for the 25-eycle 

f See Picture; 

One of the new type position-iignt signals. 

- 12 - 

traction ourrent. 

T be power supply for the signals ia a 6,600-volt line 
oonaieting of two Uo, 0, seven-strand bare copper conduotora 
strung on pin- type insulators mounted on single orosaarms and 
bolted to the catenary poles 10-feet below the 152 ,00O~volt, 
25-oyole power transmission line. The signal line is transposed 
every 3"5 miles. 

The 100 cycle current la generated at 44O volts from 72- 
Icva. motor-generator sets located along the line. The 440~^olts 
are transformed to llO-volts at the sigaaal locations by a J- or 
5 -leva., 6,600/lOO-volt transformer. 



Power for the newly electrified Sefi York- Washing ton Line 
will be obtained chiefly from the hydro-electric plant at iafe 
Harbor Maryland, where the largest singlephaae, 25 cycle, hydro- 
electric generator in the world ia being installed. This machine 
is rated at 35,OOOkva., 13,000 volts at 100 revolutions per min- 
ute. * 

The voltage will be stepped up from 13,000 to 132,000 
volts by 20,000 kva. transformers. The power will then be trans- 
mitted at 132,000 volts to the high-tenalon linea of the Pennsyl- 
vania Ballroad at Perryville, Md. 

From the high-tension lines power is distributed to out- 
door type substations located along the right-of-way. The same 
H-colujnn section poles which support the catenary system also 
support the transmission lines by use of auapenaion insulators 

UPPER right is one of twelve 
27-ft., IS-ton, half-sections 
of generator rim being rolled 
for Kanawha's six new units. Just 
above, stator frame sections are 
being bolted together into a 40- ft., 
2,000,000-lb., 82,500-kva., generator 
for Boulder Dam. At left is a 
32S,00O-Ib., 31,2S0-kva, generator 

rotor on its way to Safe Harbor. 
And below is the main shaft of the 
world's largest 25-cycle single- 
phase generator, rated at 35,000 
kva., also destined for Safe Har- 
bor, The two latter units will sup- 
ply power to the newly electrified 
New York-Washington line of the 

World's Largest Single- Phase Walerwheel Generator 

TiiP larepst ^ine-le-iihase. 2;--fvcle, hydro-electric generator ever built ^s now 

It 1^ flnn kviT liodn volts at lOO rp.xn. Power generated w U be trans- 

mit!ed at utooo voits ?o thi hiKh-tension. lines of '!«; P.Sl^^'jVv'i^^S.s^'*''- 

road at Perryvllle. Md., for use on their newly electrltted divisions 

- 15 - 

aiade up of 11 units, each unit having a dry flaahover voltage 
of 75»00O» Both hollow-core copper stranded and steel-oore 
aluminum stranded cable are uaed for the tranamisaion line. 
The steel-oore of the aluminuEi cable serves to give Inoreased 
tensile strength and the hollow-core of the oocper stranded 
serves to Increase the outside diameter of the cable, thereby 
reducing the poaalbility of radio interference. The diameter of 
the copper cable is »7'}1 in* and there are I4 strands malcing a 
total of 250,000 oir. mils. The steel core aluminum strand is 
.85 inch in diameter and ia equivalent of 500,000 oir. mils, 
copper. To offset the effects of self induction the lines are 

Power Distribution 

Ih« 152,000 volt transmission lines are fed into the 
primaries of the step-down transformers at aub3tation3*through 
motor-operated, remotely controlled air-break disconnecting 
switches. The 11,000 volt secondary of each transformer is con- 
nected through an oil circuit breaker and a disconnecting switch 
to an 11,000 volt bus. The parts of the bus fed by the trans- 
formers may be separated by a bus-tie oil circuit breaker. Power 
from the bus is fed through the requisite number of high-speed 
trolley breakers *to the catenary system. 

.aubatations of two general types are uaed. Where apace 
permits, tihe steel work which supports the buses, t^ 152,000 

volt transmission lines, and the air-brake disconnecting switches 
are at one aide and not directly over any of the 11,000-volt cir- 
cuits or apparatus in the subs tfit ion. Where spaoe Is at a pre- 

Tracks running into Penn. Station at Baltimore 

Substation near Penn. Station at Baltimore, 

Pictures showing the development of Capitol Substation 

Pouring concrete foundations froni a concrete train 

Placing the Transformers 






- 14 - 

mlum, a more compact type of substation is used, in which the 
transmission lines are above other substation equipment. 

In locating the substations, some of the more important 
consiaeratlong include the voltage regulation desired, the dis- 
tribution of loading, possible inductive effects, the proximity 
to sec tlonali zing points, and the availability of real estate. 

Ihe substations are spaced from eight to ten miles apart and 
there are 9 substations on the line from Baltimore to Washington. 

All structural footings and electrical equipment foiind- 
ations are made of concrete. The wire and electrical equipment 
supporting the steelwork is of the lattice truss type; this type 
of construction being particularly adapted for such use because 
of the high towers and long spans required, which carry relative- 
ly light loads. Also, by this type of construction, the weight 
ia reduced, wind resistance Is cut down, and visibility In follow- 
ing circuits is improved. All of the steelwork Is galvanized as 
a protection against corrosion. 

Each substation has a service trabk, which is used in 
delivering equipment and materials for construction. 

The control building is a one -story structure, of cement 
block construction, with concrete roofs and floors. This build- 
ing houses the switch control equipment; most of these buildings 
also Include signal control and the motor generator set for supply- 
ing signal power. Power switches may be controlled from this 
building as well as from the nearby interlocking tower. Power 
for the operation of switches is obtained from a amall motor-gener- 
ator charging set operating in conjunction with a storage battery. 
All control circuits are carried underground in parkway cable. 


- 15 - 

Kost of the aubstationa have facilities for filtering and chang- 
ing the oil used In the transf ornwra and switches, The ao company - 
ing pictures show some of the aubstationa. 

Power Supervision 

All switches in step-down substations, along the right- 
of-way and In yards and terminals, are controlled from interlock- 
ing towers or stations. Xhe operation of all switches in the rail- 
road power system between Washington and Jsaltlmore is super? ised 
by telephone from the power director's office located In Balti- 
more. In the power director's office is a large circuit and 
switch -indicating board, ihe main power circuits are shown in 
the diagram on these boards. The open or closed position of each 
switch is indicated by small lights at the switch locations. 
These lights are controlled by a small bench board, and '/Then a 
power switch Is opened or closed the director records the position 
of the switch by turning the light on or off. 

Orders for opening or closing any of the power switohea 
are given by the power director over the telephone to the operat- 
ors in the interlocking towera. After the order for switch oper- 
ation la given, it is performed and the interlocking operator re- 
ports back to the power director who then marks the new position 
of the switch on the Indicating board. 


The trolley supply line between substations Is divided 
into sections, and each section is separately energized through 
a high speed trolley breaker. Section breaks * between aub- 
stationa reduce the amount of track held out of aervice for re- 

Typical Power Director's Office 

- 16 - 

pair 1 

purposes to that 


two section breaks; they also 

facilitate locating troubles 

to small sections. At the section 


, th< 

i wires from c 


direct ions are carried past each 


without touching, the end of eaoh being lifted at a slight 



an insulator 

30 that 

a passing pantograph slides off of 

one V7 


and onto the 

other, ( 

sontaotlug i/7ith both for a distance 

of about 

20 feet. 

In case of a 

short oiroult or ground fault on any one of 

the catenary lines over the tracks, the section bet"veen sub- 
stations is automatically disconnected by the high-speed trolley 
breakers feeding that section at eaoh substation. Many times the 
cause of such a short circuit is momentary, and one of the high- 
speed trolley breakers may bo reoloeed to attempt to energize 
that section of catenary. If the fault persists, the breakers 
are allowed to remain open and the tower operator places a card 
on the control switch to show that it is to remain in this pos- 
ition. Steps are then taken to clear the fault, and the power 
director reports to the train dispatcher who keeps trains off 
this section of track and a^ray from section breaks so that a 
pantograph may not span the section break and energize the dead 

In yards and at terminals vhere it is necessary to feed 
contact wires over a number of tracks, a type of switch control 
has been devised which automatically isolates and indicates the 
location of a fault. The arrangement as applied to nine tracks 
is shown in the diagram "Switching Control for Yard or station 
Tracks."* Power is supplies from "A" through a single high- 

Section Break 
Contact Wires 

Blevated Insulators 

Remot e- c ont r o Ifed 
Disconnecting Sv/itoh 

Switching Control for Yard or Station Tracks 

><3 ^^S^ Speed Tr<a.ey Breaker 

Lov/ Ga^icitj* 

Oil Cirouifc Breaker 

Disconnecting p p PP P P P P P 


Trsck 1 

^ 3 4 


- 17 - 

speed trolley breaker to three low-oapaolty oil circuit break- 
era. The three oil circuit breakers in turn each feed the con- 
tact wire over three tracks through air break disconnecting 
switches, dhould a short, ground or overload, occur on tract 
Ho. 1, the high speed trolley breaker would open, this operation 
requiring one twenty-fifth of a second. During this period of 
time a relay functions to determine the location of the fault. 
After the high-speed trolley breaker has opened, the low capacity 
breaker, feeding tracks iTo. 1, 2, and $, opens and the high-speed 
trolley breaker recloses. A light indication on the control 
board shows that the fault lies on track Uo. 1. The operator may 
then open disconnecting switch No. 1 and reclose the low capacity 
breaker to re -energize tracks 2 and 5» 


The catenary system of overhead transmission derives its 
nsme from the fact that the cable from which the contact wire is 
suspended takes the form of a catenary. Xho term catenary is de- 
fined as the curve formed by a flexible cord suspended by its 

The erection of the overhead trolley was carried out in 
two main steps. The supporting structures were erected first, 
then the catenary was put in place. iSaeh step will be discussed 

The iSrection of Catenary Supporting structures, 
following carefully prepared working schedules, the 

On the 
Project . . 

Four Industrial Brownhoist special 
short-clearance cranes, equipped 
with 80 foot booms, were used by 
the Pennsylvania Railroad to set the 
poles on their great electrification 

These cranes rotate in a radius of 
only 5 feet 2 inches fronn the center 
of the car. The rear cab, inclosing 
the boiler, is fixed to the car body. 

This design is of great value in 
railroad service, particularly where 
work must be handled in close quar- 
ters. The short rear overhang per- 
mits the operation of passing trains 
on adjoining track without interfer- 
ing with crane operation. 

- 18 - 

roadway work progresses In oo-ordlnation with the other phases 
of the electrification work. One of the first and most import- 
ant 3tepa in the roadway ''ork was to secure accurate information 
oonoerning the track layout within the section to be electrified. 
Ihis was done by an engineering field party, which made a con- 
tinuous track survey over the section involved, establishing 100 
foot stations on the rail. A special set of levels was run to 
obtain the elevation of the top of the rail of the measured track. 
A set of track plans were then drawn up and turned over to the de- 
signing department for preliminary location of the catenary 
bridges or poles. She bridge spacing was established so there 
was an equal half span of catenary construction on eaoh aide of 
each bridge. Ihia put balanced loads on the poles and simplified 
the design of the catenary construction. jJhe normal bridge spac- 
ing for tangent track waa figured at 2'JO feet, Ihe span decreased 
with an Increase in the degree of curves. Variations of the bridge 
spacing were made In increments of fifteen feet in order to stand- 
ardize catenary hanger lengths. 

The proposed locations were carefully checked in the 
field, which resulted in the relocation of many bridges, //here 
the sites originally proposed could not be adopted, the field 
force recommended substitute sites and, taking there recommend- 
ations Into consideration, the span lengths were again balanced 
and the new locations were checked in the field. 

With the bridge sites finally decided upon, cross levels 
of the right of way were taken at each bridge location, and, at 
the same time, an accurate chord survey was made, using the center 
lines of th6 bridge sites as chord points. A cross section draw- 

- 19 - 

- ing was then prepared for eaoh bridge location to ahow the 
type of bridge to be erected, the apeoific type of foundation, 
and the position of all gtiya and guy anchor at* After a field 
check, the bridge foundation plans were iaaued and construction 
worJc started. 

For the construct ion of the pole footings and guy anchor^ 
the Pennsylvania developed a concrete train * equipped for 100^ 
mechanical handling and mixing of materials. These trains con- 
sist of 2 or 5 bin oars for carrying the concrete aggregates; a 
miler car, where the concrete is prepared; an old engine tank for 
water supply; and a cement oar, which carries in bulk, the supply 
of cement. To secure positive control of the quality of the con- 
crete, a two -compartment batcher, equipped with scales, ia used 
to proportion the stone, sand, and cement, which are then dis- 
charged into the elevating skip of the mixer. VVith a crew of 12 
men and material storage capacity sufficient to make from IO5 to 

120 cu. yds. of concrete, each train waa moved over the road, 
pouring pole foundations and guy anchors by the use of metal 
chutes* J!'loodllghta and a team pipes for warming the aggregates 
and water allows operations to be carried on at night and in the 

The pole footings ^onaiat of a alab mat with a center 
pedestal, the mats ranging in size from ^-K.'jT.Zii ft. thick to 12x 
12x3 ft. thick, and the pedestals ranging in size from 3 ft. 6 in. 
square to 4 ft square and ^ ft. or more in height. Both mat and 

pedestal are made of reenforoed concrete, iiiaoh of the footings 
-is poured with a vertical center well extending through the 

** See Blueprints in Appendix 

dement mixer on one of the concrete trains 

Pole footing mold used to form the pole footings — note 
can in center which forms the well after the concrete is 
poured. Reinforcing rods are also shown. 

- 20 - 

pedestal Into the base mat. 

Vim gruy anchors are of the slab type placed horizontally 
and 10 ft. below the surface of the ground. Jhe guy rod la 
housed in a steel tube filled with cement grout to prevent cor- 
rosion through contact with the ground. 

The pole footing described above is known as the grav- 
ity or "box" type. The resistance to turning over ia furnished 
by the force exerted by the earth on the under and upper sides 
of the mat. 

Another and more economical type footing is the "can" 
type. A hollow metal cylinder is driven into the ground by a 
specially designed steam hammer which is put in place by a steam 
orane. The "cans" range from 24 to 56 inches in diameter and 
around eleven feet long. After it has been driven, the earth with- 
in the cylinder Is removed, ihe bottom is flared out by removing 
earth underneath the "can". Concrete ia then poured in the cylind- 
er to the level at which the bottom of the pole is to rest. A 
steel plate is then placed upon the concrete. 

The can type depends upon the resistance of the earth 
packed around its sides to keep it in place; therefore it must 
be placed deeper into the ground. 

Two general types of supporting structures for the long- 
itudinal system are used. Where aide guya and anchors can be 
placed, a crosa catenary support is uaed, but on restricted right- 
of-way where there is no place for guys, a braced cross beaiD*must 
be used. The cross catenary type of bridge is used wherever poss- 
ible because df better visibility and lower cost. 

- 21 - 

The poles of the bridge oonstruotion, which alao oarry 
the high tension transmlaaion lines, are of the Carnegie and 
Bethlehem steel H-section type. They weight from 84 to I03 lbs. 
per foot and range from 70 to 110 feet in height. 

Ereotion of the poles is aooomplished by the use of 
specially designed steam oranes with extension booms, a pole is 
set upright with Its lower end in the well of the footing, and 
stone spacers are dropped to the bottom of the well to oenter the 
base of the pole; then oak wedges are driven around the top open- 
ing to support the pole temporarily while it is being plumbed by 
the use of transits. The base is then concreted in up to the 
wedges which are removed after the oonoz'ete hardens, after which 
the concrete work is finished. In subsequent operations, the 
transmission line orossarms are bolted in place, the cross caten- 
ary or beam bridge is erected, and the poles are given two field 
ooata of aluminum paint iJor protection against corrosion. 

The supporting structures are then ready to "take wire." 

The Erection of the Catenary* 

The cross catenary proper or supporting cable consists 
of a 19-strand, bronze o"ble, 5/8"» 5/4". or 1", in diameter, de- 
pending upon the loading. It Is connected to the two H-section 
poles by U-bolta and Is fitted with a turnbuokle for adjustment. 

A horizontal cross wire, known as the body span, similar- 
ly connected to the poles. Is supported from the cross catenary 
by dropper rods and clamps. 

Immediately below the droppers from the cross catenary 

6-3?7aSTif46' TMSULft-njitS 

- 22 - 

are hung the s-uspension type Inaulatora which support the main 
or longitudinal catenary or messenger. Xhis oonaiata of 5/S"» 
19 3 trend, bronze oahle, having a oooper equivalent conduct ivity 
of 15^. The next wire below that is the auxiliary messenger. 
It is a 4/0 grooved solid copper wire and is supported from the 
main messenger by bronze hanger rods. The hangers are spaced 30 
feet apart on tftngent trnok and I5 ft. apart on curved track. 

The contact wire is a 4/0 grooved solid bronze wire with 
approximately 40,^ copper equivalent conductivity. It is supported 
from the auxiliary messenger by oast bronze clips spaced I5 ft. 
from each other. 

With the above arrangement it is possible to replace worn 
contact wire without disturbing the catenary. The contact wire 
oan be made stronger and tougher even if the conductivity is in- 
creased for the auxiliary messenger carries practically all of the 
current to the nearest point of contact (clips) of the messenger 
and contact wire where the load Is located. 

Jour general types of catenary are used: tangent cstenary,* 
catenary for curves up to 2deg. JO mln.,* catenary for curves from 
2 deg. 50 min. to 4 deg., and catenary for curves greater than 4 

The erection of the catenary is carried out as follows; 

While the guys end cross catenary are being put up, a 
separate crew applies cross arms and insulators preparatory to 
the stringing of the transmission line wires, ihe structures are 
then "ready to take wire". 

The transmission line wires and longitudinal catenary 
are strung simultf^neously by separate crews. The first wire of 

gt-R.r T£flfM WLTH TOuDETi Cft«^ IA563> TO C^ecT "^^ eflT^/^£.Y 

r*IMtll •* •* * ■» *^ ■» " ■» J '■> '^ r- .. ' - ' 

^oiLmm Pu^c'^^ riftHSses ^*£^ -^^ suPf^er 

-^e ctjt^ I'Wrr 

Tangent Catenary with Cross Catenary Support 

Inclined Catenary for Curves from 2 Deg. 30 Min., to 4 Deg. 

- ^3 - 

the tranamiaaion aaaembly is the ground wire, following which 
the four tranamiaslon line wires are strung in sequence, iho 
wires are pulled from a stationary reel on the ground over sheaves 
hung on the poles. Saoh reel contains about a mile of wire, and 
after this is strung out it is tensioned with bloclc and taoicle 
and a tension dynamoine ter. The sheaves are then removed and tht 
Insulator olampa applied. 

The stringing of the messenger wire for the main or long- 
itudinal catenary requires traok occupation. The work is done with 
a wire train* consisting of a tool and material car, a reel oar, 
tower oar or cars,* locomotive and caboose. The tower cars have 
platforms of adjustable height. 

One end of the messenger cable is taken from the reel, 
connected to a permanent attachment, and strung loosely over 
sheaves, which are hung from the insulators on the cross catenary. 
When the end of the wire is reached, the elaok la pulled, the wire 
given preliminary tension and snubbed to the nearest availabl* 
structure. The wire on another reel is then spliced to the first 
and the process continued for three or four reels. All the wire 
is then pulled to a greater tension and intermediate snubs at the 
wire Joints are removed. The tension is then increased to some- 
thing greater than specified unloaded tension, and the cable la 
left under this tension for two or three days to allow for equal- 
ization of tension in spans. The tension is then tested at inter- 
vals along the wire by a shunt dynamometer. This measurement 

serves to determine whether or not the tension Is correct. The 
adjustment of the tension is given much attention, as uniform 

Beam type supporting structure used when there is no space 
available to place guys necessary in the cross-catenary 
type of bridge. 


' - i. ,■ 

— »»« 












^N^■ ■ 





^■■^ '-'. 

■ ^ 





Method used to support catenary 
over tracks at Union Station. 

- ? 

4 - 

tension of the main messenger ia pre-requiaite to a aatis- 
faotory catenary system. To equalize the tension, the wire is 
pulled at several points , and every effort is made to see that 
slack is carried through each support. 

The next operation is the application of the hangers to 
the main messenger.* These are made up in the shop to different 
lengths from computed tabulations and are applied by wiremen 
riding the messenger in boats^vain*s chairs. Position of the 
hangers is determined by measurements made along the rail. 

The auxiliary messenger and the contact wire are strung 
out simultaneously and supported temporarily by wire hangers while 
they are pulled to approximate tension, temporary splices are 
made bet'veen the wire ends and ss much wire as possible is snubbed 
to a preliminary tension. Then the tension is pulled at each 
temporary splice with block and tackle and a tension dynamometer, 
and the permanent joints are made. Both wires are pulled at the 
same t ime . 

The final operation of catenary erection Is the attach- 
ment of steadies and pull-off 3, testing the alignment of the 
trolley with that of the track, and making final adjustments. 



There are four types of electric locomotives now In use 
on the Pennsylvania lines. The class P5 locomotive for heavy 

Locomotives Ncnv In Use 

Cl'^'SS LG LocDTnotive for Henv^- Duty Freight 

Class P5 Locoinot.ivs for He^vy Duty Passenger Service 

Glnss 01 Locomotive for Light Duty Passenger S^arvice 

- 25 - 

duty paaaenger aervioet having a 2-C-2 or 4-6-4~whe9l arrange- 
ment; the class 01 looomotive for light duty passenger aerriot* 
with a 2-B-2, or 4-4-4 wheel arrangement; the olses L6 locomotlTe 
for freight 8ervice*haTing a 1-D-l or 2-8-2 wheel arrangement, 
and the olass B-1 awitohing locomotive with an 0-C-O or 0-6-0 
wheel arrangement. 

lo facilitate and simplify maintenanoe , special attention 
has been given to interohangeability of parts. Any unit or part, 
armature, motor, brush holder, transformer or oontrol unit on 
any P5 looomotive will fit into and function properly in any 
other ^5 locomotive assembly, regardless of the manufacture of 
other parts in that assembly. The passenger locomotives and the 
freight locomotives are so designed that the maximum number of 
parts are interchangeable. 

^oh complete locomotive assembly consists of three units: 
A chassis unit, a deck unit, and a oab unit, iiach of these units 
may be assembled Independently of the others and the complete units 
may then be assembled into a locomotive. 

Every effort was made to insure that each piece of appar- 
atus Is readily access ible for inspection and readily removable 
for repair, so that a looomotive may have a defective piece of 
apparatus replaced and be returned to service in the minimum amount 
of time, i'or this purpose hatches are provided in the roof of all 
three classes of locomotives. These are readily removable and are 
80 arranged that any piece of apparatus inside the cab may be 
taken out through one of the hatches for repair or replacement. A 
complete driving wheel assembly, including the motors, may be drop- 
ped from the frame in the repair shop, thus making all electrical 

- 26 - 

parts of the locomotive readily aoceaaible either from above 
or below. 

The following desoription of the oonstruotion of the 
P5 heavy-duty passenger locomotive applies general to all of the 
locomotive 3. 

The P5 locomotive with its 2-G-2 wheel arrangement has 
a rigid frame bet-veen couplers. The cab ia mounted directly on 
the main frame. There is a four-wheel truck at each end and 
three pairs of driving wheels in the rigid wheel base. Water and 
fuel tanie and main air reservoirs are embodied in, and oast with, 
the main frame. The engine truck frames, as well as the main 
frame, are of the integral cast steel type. 

T he weight of the locomotive is distributed to the wheels 
by an equalizing system consisting of main springs and equalizers 
providing a stable system in lateral as well as longitudinal planes. 
The bra^e system consists of practically three seta of brakes, 
each engine truck having its own set and the drivers the third. 

The wheel centers are of cast steel, having eight spokes 
provided with pads for receiving the torque of the motors as trans- 
mitted through the gears and quills to the driving wheels. Th« 
tires, which are four inches thick, are held on by shrinkage and 
retaining rings. The outside drivers are flanged and the middle 
driver ia plain. 

There are three twin armature traction motors *on the 
locomotive, supported rigidly from three points on the crosaties 
of the main frame. S,&oh motor is rated at 625 tp. continuous at 
the driver rim, thus providing 1250 hp. per axle. The performance 


- 2? - 

character iatio of the two types of passenger locomotives are the 
same ao that they may be operated separately or in any desired 
csomb inatlon. The voltage for the motors varies from 224 to 96O. 
Ihe motors are connected in two groups of three in series. 

The traction motors transmit power to the drivers 
through the quill type cup drivef the driving memtier being on one 
end of the quill only. The quill consists of a hollow cylindrical 
forging 15 inches in diameter at the quill bearings, with the 
gear mounted on one end. The driving axle is inside the quill; 
there is l| inches radial clearance between the axle and the In- 
side of the quill to permit freedom of movement between the axle 
and the motor frame whil» maintaining accurate mesh of the gears 
and pinions. The quills are secured to the main motors by bear- 
ing caps on the main motor frames, iill the movement between the 
driving 'vheels and the quill is talcen up b;; sliding contact be- 
tween the quill spring caiDS and the driver spokes. The quill arms 
with their spring sockets are attached to the gear center and 
make contact between the driver spokes. Each armature has a pin- 
ion on the quill, and the power is thus transmitted from the motor 
to the drivers. 

The cabs are built up of sheet plates and structural 
shapes. A separate deck*for mounting the electrical equipment is 
30 designed that it can be handled as a unit and placed in posi- 
tion on the main frame by a crane. The apparatus deck*oarries 
the main control groups, air compressor, miscellaneous items, main 
wiring and moet of the control wiring. The foundation for this 
unit is a structural framework upon which the electrical equipment 



1250-hp. G-E traction 
motor (3 on each loco- 
motive) with ipring-cup 

Elechric Motor Showing Quill Typ's Cup Drive 

Close Up of One o-" ':,h<j ivrxn ^ottn's Sho^'fing Control 

- 28 - 

is assembled and wired up; the completed unit ia then ready for 
mounting on the chasais. 

The oab* forma a weatherproof housing for the loaomotive 
orew and apparatus. It is suffioiently wider than the apparatus 
deck to permit and aisle on either side and enough longer to fur- 
nish space for the heating boiler at one end, the main transform- 
er at the other, and an operating compartment at either end. Ihe 
cab structure, also contains the master controllers, and engineer- 
's brake valve ^ the lighting and its wiring, some of the control 
wiring, the bells, whistles, headlights, sanders, and pantographs, 
as well as the louvre structure for admitting ventilating air to 
the motor and transformer blowers. It is assembled as a unit, 
wired and equipped with apparatus and mounted on the chassis unit 
after the deck unit has been installed. 

J?he pantograph or current collectors are mounted on the 
roof, one near each end. In operation, current la collected from 
the trolley wire by one of two pantographs and la thence conducted 
through the high voltage or primary winding of the main transform- 
er to the rail or ground. The two pantographs are connected by 
a high-voltage bus and, in case of damage to either pantograph, 
the bus can be divided at the center so that the damaged panto- 
graph can be disconnected and the transformer supplied by the re- 
maining one . 

Current is taken from the low-voltage or secondary wind- 
ing of the main transformer to the traction motors. There are 
a number of taps on the secondary of the tranaformer and the volt- 
age to the motors can be controlled by changing the taps to which 

pEuitograph used to collect 
Current from troley 


M«in Frame t'j Motors 

Equipment Deck 

Locomotives Heady for the Finishing Details 

29 - 

the motor leads are eonneoted. Thia is acaompllahed by air- 
operated switohea oontrolled eleotrically from the operating 
cab. When the looomotive la moving slowly the voltage applied 
to the mo tor a Is low. Ihe counter -electromotive force generated 
by the motors is also low and the amount of current la relntlvely 
high. AS the locomotive apeed increases the amount of current 
flowing through the winding decreases and the voltage is again 
increased by the operator to provide the necessary power. 

Only low-voltage battery current is used In the control- 
lers in the englneman'a oab and all high-voltage equipment and 
circuits in the locomotive are enclosed. Dhe equipment compart- 
ment contains the high-voltage apparatus whioh la protected on 
each aisle side by screens an^i covers. 

Mo tor -driven blowers for oooling the motors and the 
transformers are operated from the main transformer on a 584 
volt tap. Single -phase motors for this purpose are equipped 
with a starting winding which ia cut out by a relay that func- 
tions when air pressiire on the blower discharge has risen to a 
pre -determined value. 

The compressor motor, the cab heaters, and the blower 
motor for the oil-fired train-heating boiler are operated from a 
224-volt motor tap. The operation of the compressor motor ia 
controlled by the air pressure in the main reservoir; the eleotri- 
oal cab heaters are manually operated, and the air pressure to 
the boiler burner ia controlled by the steam pressure through a 
damper in the air duct. Air pressure at 'JOtt per square inch for 
for the operation of electro-pneumatic switches is supplied from 

- 5o - 

an auxiliary reservoir w'niah is fed from the main reservoir 
through a reducing valve. 

Direct ourrent power at 32-volt3 for the operation of 
oontrol clrouita and emergency lighting is supplied by a gener- 
ator operated by the same motor as the transformer blower and 
operating in oonjunotion with a storage battery. When the panto- 
graph is up the lights are supplied by a small transformer, the 
primary of whioh ia connected to a 144-volt tap on the main trans- 
fornier. When the pantographs are do'vn, a relay disconnects the 
lighting oirouits from the lighting transformer and oonneota them 
to the storage battery. 

Faults or grounds in the seoondary wiring to the unit 
switches and in the transformer windings are detected by a relay 
whioh selects the defective olroult and opens the controlling 
switches, or if this does not olear the trouble, or if the fault 
is in the transformer itself, closes a switch which grounds the 
pantograph, causing the adjacent substation breakers to open. 
After the line is de-energized, the relay lowers the pantograph. 

Overload of a motor circuit causes that circuit to be 
opened; this ia indicated to the enginetaan by the lighting of a 
signal lamp and by the operation of an alarm buzaer in the cab. 

Differential voltage relays check the relative values 
of voltages across the motors on different wheels, and should the 
speed of one wheel rise as compared with either of the others due 
to wheel slippage, the relays will serve to disconnect the motors 
and prevent overapeeding. The englnenmn is also apprised of this 
aotion in advance by a lamp and buzzer, ao that he can normally 
anticipate the operation of the slip relay by shutting the power 

- ^1 - 


part way off until the wheels oease slipping. 

The oil-fired train-heating boilers are of the vert- 
loal tubular type and hare an evaporating oapaoity of 4t500 i^» 
of water per hoiir at 200 lb. pressure, Water level and a team 
pressure are maintained automatically. Adequate safeguards are 
provided to out off the oil supply in case of low water or other 
emergencies. Air for combustion is furnished under pressure by 
a separate motor-driven fan. Control is entirely automatic 
after the boiler has been fired up. 

New lype Loeomotives. 

I'he Pennsylvania xiailroad recently placed an order for 
57 Jiew eleotric locomotives, described as the moat powerful elec- 
tric passenger locomotives ever built in the world. They will 
be capable of raaJtlng a regular operating speed of 90 miles an 
hour and will cost around |25O,OO0 each. Ihey will be 80 ft. in 
length, weigh 460,000 pounds, and develop a maximum starting 
tractive effort of 72,600 pounds. i?ovTer will be furnished by six 
pairs of t'vin traction motors somewhat similar to those used in 
the present entrines. Xhe main changes include the articulation 
of the main frame with three sets of driving wheels per section, 
streamlining of the oab to give a more pleasing dhape, placing 
the crew in the center, and mounting the headlight in the doora 
at either end of the locomotive. 

The Fust of \J New Etectric Passengef Lcccmctivei 'vVhicli Are Fa;! cf the Pennsylvania ElectrificatiL;i; i'';u]ect 


Pennsylvania .iiailroad officials olaim that electric motive 
power provides the moat eoomomlGal means of railroad transporta- 
tion when the traffic density justifies its Installation. 

Ihe Electrification Program of the Pennsylvania --tailroad 
represents a great forward stride in the development of the rail- 
road system, and although the initial investment will be high, the 
ultimate savings and benefits to the railroad, industry, and the 
public will more than justify this great engineering achievement. 


Mr. fl. i'. £9rry - Blectr5oal iinrlrf pring- L^rartrpnt, P.xL-t. 

Mr. Wm. B. Kraft- Aaslstant Comptroller, P.fJi-J, 

Mr. Chaa. iiogan'$2 - Inspector, Capitol oulastation^ Wash.^D.C. 

Ur. Klauter - InsToectdr, Union Substation, 'A'agh., D.C. 

Mr. Foltz - Eleotrioal Engineer, Washington terminal 

Mr. Bounds - General superintendent^ Union Station, Wash., D.C. 

Mr. E. A, Freeman - Gataloger, Bureau of Hallway Economies, Wash. 

Foremen, Inspectors, and Employees P.iiH, 

Interstate Commerce CommiSKion -finance Uoc^et r9245 
> <■ Gommeroial and Jj'inanoial Chronical - Jan. b, 19^4 

Hallway Age - ij'eb. 25, 1955, ^'^^* 17. 1934, ^^o^. 24, 19$4 

Railway Electrical Engineer - Uov. I928 

Electrical Engineer - /eb. 1954 

The Evening Star 

The Baltimore Sun 

l*ennsylTanla Railroad Company Annual rCetiorts 


- 3 

ilghtning Protection 

Lightning protect ion for the l>2,00-rolt line ia in- 
aured by a 4/0"3 branded copper ground wire run above the trana- 
miasion line along the tops of the poles. The ground wire sup- 
port on each pole make a an electrical oonneotion and the poles 
are gromided at oertain points to the Impedance bonds at the 
track joints. This ground wire is in parallel with an inductive 
neutralizing and lightning protective underground wire which is 
also connected to the rails. At the substations the transmission 
line ia protected by spark gaps, and by reducing one strain in- 
sulator string to 7 instead of IJ units and placing arcing rings 
around the end units. 

Lightning poles are used for protecting the substations. 
They extend above the structure high enough to protect all appar- 

All lipOO-volt circuits are protected at the substation 
by lightning arresters* One arrester is connected to each feed- 
er between the high-speed trolley breaker and the catenary. 


five types of insulators meet praotioally all of the 
requirements of the electrification. 

The Bl insulator has a diameter of 10- inches and a 
spacing bet'veen units of 5* inches. It is a clevise type sus- 
pension insulator and is used both for catennry and transmission 
line. It has an ultimate mechanical strength of 12,000 lb., and 
ia used with a maximiuD working load of 4,000 lb. I'hree units in 

• 34 - 

a string are used in the 11,000-TOlt oatenary and 11 units for 
auapenaion insulators in the tranamiasion line. 

The 11 insulator has the same dimensions as the Bl, but 
has an ultimate tensile strength of 20,000 l"bs. It is used only 
for the oatenary. 

The A2 insulator was designed for oatenary dead-end; it 
is 12 Inches in diameter, and the spacing bet'veen units la 5i in. 
It is of the suspension devise type and has an ultimate mechan- 
ioal strength of 30»000 lbs. It is used for loads up to 10,000 

The type 3 , insulator is a two-part, pin type xmit, 
haying a ft in. minimum overall dimension and a 95.0'^0~'"olt dry 
flashover, and serves to carry the signal b,600-volt power supply 
line . 

The type L Insulator was designed eapecially for tunnel 
and under bridge oatenary support. i?he insulator has a height 
of four inches per unit, and the assembly is made up of three 
units. Each unit has a dry flashover voltage of 70,000 and an 
ultimate tensile strength of 15,000 lbs. In order to resist 
the aide pull from the oatenary at the bottom, the insulator 
assembly was designed to stand an ultimate load of 2100 lbs. 
applied horizontally at the catenary support. 

Hew Calculating Machine, 

One of the interesting pieces of equipment is an alter- 
nating current calculating board purchased by the railroad to 
eliminHte tedious calculations of complicated circuits involving 
transmiasion, distribution, and moving electrical loads. On this 

tooard» the values of reaiatanoe, inductance, and capacity 
to be found in practice are set up in miniature and corres- 
ponding minature values of voltage or current with suitable 
frequency and phaae relationships are applied to the circuits 
Set up. With conditions thus established on the main switch- 
board, meters on a control board can be inserted in or connected 
to any desired part of the circuit to show what the value of 
current^ voltage or phaae angle is at any point in the circsuit.