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Pennsylvania RR Electrification

Without a doubt, the greatest electrification project in North America is the 400+ route-miles of the Pennsylvania Railroad's Eastern Corridor.

With as many as 12 tracks of various roads running between New York and Washington (Pennsy has 6 tracks north of Philadelphia) the traffic is still so dense that Pennsy has to consolidate its trains to keep things moving.

Maintaining the rigid schedules and tight movement clearances with 18 and 20 car consists requires quick acceleration and high sustained speed. Only heavy electrification could do the job. These are the "motors" that did it.

Electrification came to the Pennsylvania Railroad as early as 1895 when a PRR subsidiary transit line in New Jersey received third rail. This short lived experiment, involving a single wooden trolley car, proved less than desired. When the power station burned to the ground, the effort was abandoned and the run reverted to steam power.

The real story began in 1905 with electrification of the Long Island Railroad and various transit districts, and in 1906 when the new Penn Station (New York City) and the tunnel under the Hudson River were begun. These projects are all of the transit line and terminal district breed: using 650 volts DC supplied by third rail. Motive power is mainly MU cars, although the first significant heavy power, the DD-1, made its appearance in 1909.

By 1910, the system was complete, with long haul trains exchanging their road power at Manhattan Transfer, being hauled under the Hudson to Penn Station, and then on to Sunnyside Yard, Long Island, for servicing and reassignment.

They then turned their attention to the congestion around Broad Street Station, Philadelphia. Commuter service is a problem here too, and the terminal area and several local lines received electric power. Here, however, two major breakthroughs were made: for the first time, the electrification is overhead catenary delivering 11,000 volt AC at 25 cycles; and for the first time, a portion of the Main Line, from Philadelphia to Paoli, is under wire.

This was basically another commuter district: the crude electrical engineering of the day was not up to long haul high speed service. The ever increasing traffic demand in the eastern corridor made long haul electrification an attractive concept, but there is a long development process ahead. Pennsylvania Railroad electrification, which would one day rule the east, had to crawl before it could walk and walk before it could outrun the prodigious K4s 4-6-2.

The "Universal" Side-rodders

The electrification in terminal areas in New York City started in 1905 when the decision was made to electrify the new Pennsylvania Station, then in the planning stages. Following the pattern of the time, 650 volt DC third rail was adopted as the standard and plans laid for an electrified district from Penn Station under the Hudson river to the New Jersey terminal soon to be known as Manhattan Transfer.

At the same time, Long Island MU commuter service, using the same third rail, was growing eastward. For the moment, new concepts in MU cars - which would lead in due time to the legendary MP-54s - would soon be handling the commuter traffic. However, looking ahead to the time when the tunnel was complete, it was obvious that some sort of heavy road power would be needed.

Thus, in 1905 a committee was formed to create a heavy electric "motor" (as electric locomotives have come to be known). This committee of the top Pennsylvania Railroad and Westinghouse engineering talent soon turned out a pair of basic box cab B-B units numbered 10,001 and 10,002.

These were little more than compressed trolley cars with steel bodies and they quickly proved inadequate to the task. They each had 4 MU type traction motors which simply could not deliver the power needed for heavy main line trains over the anticipated 2.2% grade in the Hudson River tunnel.

Moreover, they were rough riding and the unsprung motors were damage prone at speed. After a period of experimentation, #10,001 went to the Long Island, where it was known as "Phoebe". #10,002 was renumbered "9" and dubbed "the covered wagon" by PRR crews. Both motors went to switching duty in Penn Station and Sunnyside yard until scrapped in 1937.

Building on experience, the Committee went back to the drawing board. Realizing that a super-MU would not work, a new concept of a box cab with a huge heavy duty motor powering large drivers by jack shafts and side rods evolved. This began a trend. Over the next few years, several designs of what have come to be called the "Universal side-rodders" were created. These "Universal" motors would rule the PRR until the 1930s, when evolving electrical technology made them obsolete.

Pennsy's first production lot of road power are the box cab DD-1s. The first of these appeared in 1909 and helped with the tunnel construction. They continued to arrive in batches until, in 1910 when Penn Station opened, the entire lot of 24 pairs was on the property.

These are a very simple design: a pair of 4-4-0s articulated back to back (in PRR nomenclature, a 4-4-0 is class "D"). On each of these chassis is a huge DC motor - 6 feet in diameter - mounted sideways on the frame. These motors drive a jackshaft (an idler wheel that powers a steam locomotive-like main drive rod) which powers the two drivers through standard side rods.

Power pickup is by contact shoes bolted to the pilot trucks and resting on the third rail. There is no transformer: the motors take 650 volt DC power directly off the rail. There is no gear reduction: part of why the motors are so large is that they turn at the same speed as the drivers - usually less than 100 RPM.

While they are capable of running 80 MPH, the DD-1s seldom reach top speed. With only 2130 HP, the heavy steel trains are quite a load on the steep grades of the Hudson River tunnel. However, as they are on a short terminal district, the DD-1 pairs can double head if needed and scuttle back and forth between incoming and departing trains.

In this capacity they served Penn Station's needs until the completion of the catenary line from Washington, D.C. in 1933. With road power now able to run directly into the station, Manhattan Transfer was abandoned. A few of the DD-1s continue to serve as terminal and yard power, but most have been transferred to the Long Island Railroad, where they serve as long haul power.


One of these units was assigned to MOW service in the tunnel complex, thus assuring its later preservation. It is now at the Pennsylvania Railroad Museum, Strasburg Pennsylvania.

With the 11,000 volt catenary around Philadelphia complete, the Pennsylvania Railroad began to develop it's first heavy AC road power. Altoona, in cooperation with Westinghouse, created an unlikely looking super-steeple-cab classed as the L5, number 3930, which was fielded in January 1924.

While this was going on, the demand for further 3rd rail power in the New York City terminal area was growing acute. The prospect of long haul AC electrification was still very much up in the air due to the rapid flux of electric technology and it would be years before through service would come, if ever.

In the mean time, traffic loads were spiraling ever upward. Hope that the DD-1s could handle the increased demand by themselves until help arrived was fading. With the prototype L5 turning in some impressive results on the Paoli grade, Philadelphia decided to adapt the design to create a 650 volt DC version. The first two of these, turned out in late 1924, were dubbed the L5a.

The design features two massive plate mainframes bolted to two equally massive motor housings. As with the DD-1s, the L5a has two large motors (which have shrunk enough that they can be built into the chassis between the driver assembly and the pilot truck). Power is transmitted via side rods to two sets of paired drivers. Unlike the DD-1, these motors are rigid frame duplexes (they were classified type "L", 2-8-2s, because Pennsy nomenclature does not have a class for 2-4-0s).

The two L5as were soon reclassified as L5PD (Passenger DC power) and 21 more units were ordered. These came with a variety of electrical systems (which proved a maintenance headache) resulting in several sub classes:

In February, 1927, the original L5 was rebuilt to resemble its brethren, reclassified as L5PAW (Passenger AC Westinghouse) and was reassigned to over the road passenger service.

Despite their impressive 80,000 pounds of starting tractive effort, the L5PDs have proven unsatisfactory. Although the two center driver sets are blind, they have to be restricted from tight trackage in Penn Station and Sunnyside Yard. They suffer frequent brake rigging bindup because the long rigid frame amplifies every uneven spot in the track. There are also frequent lubricator problems and short circuits.

Nonetheless, the demand for motive power kept them in service through the years before the arrival of the AC electrification. With the arrival of the 11,000 volt catenary in 1933, most of the side rodders have been pulled out of service and are up for reassignment. The Long Island railroad, knowing the problems of the L5PDs, were not willing to take them (although they gladly accepted the DD-1s!)


After leaving Penn Station, the L5 classes had no other place to go. With the cost of rebuilding them for AC service being prohibitive, they lingered on the roster until 1942, when they were scrapped.


The "electric stream engines"

In 1927, a major breakthrough in electric motor engineering resulted in a high horsepower traction motor small enough to fit between the locomotive frames and to be geared directly to the wheels. A 600 volt, 625 HP AC motor was soon perfected which eliminated the jackshafts and side rods and greatly improves reliability; making high speed passenger road power practical.

This development had a profound effect on Pennsy electrification. What had, until then, been an electrified helper district could now be expanded into a reliable long haul system. As a result, the formal go-ahead was given in 1928 and the wires began reaching north toward New York City and south toward Wilmington and Washington, D.C.

By 1931, when the first production road engines began appearing, the wire stretched from Trenton, N.J. via Philadelphia to Wilmington, Delaware. New York City was reached by 1933, and Washington early in 1935. The electric zone was then extended west from Philadelphia, reaching Harrisburg by 1938.

Pennsy employed some outstanding steam technology on their eastern lines and the demand for motive power had resulted in 4-4-2s, 4-6-0s and 4-6-2s being turned out in hundred lots. With this record to build on, early efforts in electric road traction have been focused on creating electric versions of these dependable steam power.

First out of the chute are the O1 class 2-B-2s: intended as a replacement for the E6s Atlantics. The O1 series is something of a test bed: 2 each of 4 different subtypes, O1a, -b, -c and -d were built- each with minor variations on internal hardware.

The design is basic: the main frame is one huge steel casting with drivers and pilot trucks equalized in the usual manner. The two driving axles each have a pair of 625 HP motors on floating mounts. These are geared to a large pinion gear which, in turn, powers the drivers through a "spider" assembly that fits between the wheel spokes. The four motors produce a total of 2500 delivered horsepower with a top speed of about 90 mph.

Above this is a steel deck. The transformer, air pump and other auxiliary equipment is mounted on this deck and a box superstructure of riveted aluminum put overall. The air tanks and cooling coils are slung along the side of the carbody.

The carbodies have no internal dividers and are ventilated by numerous grilles:; one crew complaint is that they are drafty and bitterly cold in winter. There are control stations at either end. The roof carries two scissors type pantographs developed by Westinghouse. Large hatches in the roof allow major equipment to be removed for repair, or the entire cab can be lifted bodily off for chassis work.

When the O1s were originally conceived, the typical passenger train was about 9 to 12 heavyweight cars; which the E6s could handle comfortably at 60 mph. As traffic increases on the Eastern Corridor, Pennsy has been forced to consolidate two or three trains into one whopping 20 car consist in order to keep things moving. Another essential to reduce traffic congestion is to increase running speeds; with 90 mph as the new goal.

The problem with the O1 is that they are just too small. With only 2 driving axles, the O1s simply lack the capacity to handle such large trains even when double headed. They are also slippery and have a severe problem with side-to-side nosing at high speed. Simply put, they have been passed over by the tide of events. While many useful lessons have been learned from them, production ceased at 8 units and they have been bumped down to commuter service.

Building on experience, Altoona next tried to duplicate the K4s 4-6-2. Essentially, this new motor, dubbed the P5, is the O1 stretched out and given an additional driving axle. The two initial units delivered in 1931 turned in some promising results, so Pennsy ordered them into production.

The P5a (the production version) solves many of the O1's problems. With more power they can handle as many as 15 cars and better traction from the extra driver makes them less slippery. This allowed Pennsy to increase running speeds to 90 MPH. Beyond this, average speed increased sharply as the P5a's overload capability keeps them moving briskly up the grades coming out of the Hudson and Potomac River valleys.

However, while the P5a is good, and things went along smoothly at first, the design soon began to show its shortcomings.

The original electrification concept had presumed that the motors would be double headed as needed: a practice originating from Pennsy's 400 or so E6s Atlantics. In fact, paired P5s can handle any train that can fit into the passenger terminals. However, as the electrification costs keep mounting, the home office in Philadelphia has been rethinking this premise.

There is also the nosing problem. At high speed, these motors swing forcefully side to side. While the pilot trucks absorb some of this sway, it is still enough to damage the track. Moreover, Philadelphia has always been supremely safety conscious, and the idea of these brutes slamming back and forth at 90 mph must send chills down their collective spines.

Then there are the axles. It was soon discovered that the tremendous bursts of power are twisting the axles so much that they began to develop cracks. Heavier axles has helped this problem, and improved suspension helped the swaying. But the basic concept of a rigid framed unit with a lot of power on a few axles has proven to be less than might be hoped.

In 1934, one of the P5a box cabs was involved in a grade crossing collision with a dump truck. The aluminum cab was crushed and the trainmen killed. This tragedy renewed the long standing trainman's fears of riding in the exposed box cabs. At the same time, another inherent problem has become evident: the crew sits very close to the track with nothing to obstruct their view of the ties as they whip past. They are experiencing what has since become known as "highway hypnosis".

At that time, 28 P5as were undelivered from the original order, so Baldwin developed a modified center cab version based on the then-pending GG-1 concept. Like the GG-1 (and unlike their box cab brethren) these motors have a steel bridge truss chassis- making them almost indestructible. The cab has been relocated to the center and raised about two feet, which protects the crew in the case of another grade crossing accident and gives them improved visibility as well.

Aside from that, these new motors are identical to the earlier box cabs and can be used interchangeably. Known as the P5am (modified), the last 28 have taken over much of the passenger duties pending the GG-1s arrival. This allows some of the box cabs to be bumped down to freight service, where they run more comfortably at lower speeds.

Like the P5as, these motors, when double headed, can handle any train Pennsy can put together. When running in multiple with a box cab P5a, the P5am always takes the lead because of its improved crew safety. Ongoing research has improved (but not entirely eliminated) the side to side nosing problem and the axle cracking as well.

When the GG-1s finally arrive, the P5ams will be demoted to handle an assortment of freight, express, secondary and commuter passenger trains. The box cab P5as will go exclusively to freight service.


The last of the P5as was withdrawn from service in the late 1960s. The original P5 box cab, #4700, is preserved at the National Museum of Transport, in St. Louis County. The rest, including all the P5ams, were scrapped. (The early complaint that they are extremely rough riding was later borne out when the #4700 derailed repeatedly while being moved around the grounds of the museum.)

One of the most powerful and efficient electric locomotives ever developed - and certainly the most handsome example of the streamlining period - are the 139 GG-1s. Nominally rated at 4620 HP, these motors can double that figure for short times; allowing them to handle 20 car consists with ease. In one test conducted shortly after the first batch were delivered, a GG-1 produced slightly more than 10,000 HP on the rails.

Learning from the P5a experience, Philadelphia has reconsidered the whole electric concept. The "electric steam locomotive" idea isn't doing well and the growth of power requirements is outpacing engineering progress. Something new is needed. Whatever it is, it has to be big, powerful, agile and fast: and it has to be developed quickly as the Corridor electrification project is nearing completion.

Somewhere along the line, they borrowed one of the new box cab EP3a 2-C+C-2 motors from the New Haven Railroad. In exhaustive tests against the P5a, the EP3a showed far better acceleration (though geared for 120 mph) and rode smoothly at speed. This set off an acrimonious debate in Pennsy motive power circles: many staunch advocates argue for an improved P5a with a 2-D-2 wheel arrangement, while others feel that the articulated machine, though it has more axles, joints and motors, has better growth potential.

To settle the matter once and for all, orders were placed for a single 2-C+C-2 and a 5000 HP 2-D-2, to be classed the R1. This R1 seems to have been the odds-on favorite, for it received a number in the proposed series while the GG-1 was given a higher number. In tests, the double jointed GG-1 carried the day, though the R1 was reported to be a serious contender. Still, the riding quality just isn't there. The R1 was never duplicated and went to the general service pool, while the G motors started arriving in quantity.

Following the Altoona/Baldwin tradition, the chassis is cast steel, jointed in the middle like a mallet, with pivot motion pilot trucks. The 57 inch drivers are each powered by two motors as before, but some major changes have been made. These motors are also smaller: 385 HP - almost identical to those used in the swarms of MU cars.

The carbody is built like a through-truss steel bridge. The main transformer and train heat boiler are mounted in the central cab area. Outboard of that are the two crew cabs (which are very crowded and tiny) with the air pump, sand boxes, fuel and water for the boiler and other auxiliary equipment stored in the narrow outboard hoods.

This truss carbody gives the GG-1s enormous structural strength. In one case, #4876 lost her brakes, plowed through the wall of Washington Union Terminal and crashed into the basement. They had to cut her into three sections to extract her. The pieces were welded back together and the motor returned to service.

These are the last passenger electrics the Pennsylvania Railroad bought in any significant numbers, and very nearly the last large lot of electric power of any sort. With the 139 GG-1s in place (backstopped by the 92 P5s) Pennsy was well prepared for the wartime traffic deluge. In the postwar years, the G motors have proven to be durable and dependable, and will serve the Eastern Corridor until 1980.


The GG-1s started retiring in the mid 70s, and the last- then in commuter service- retired in 1980. At least 15 have been preserved by various museums, Historical Societies and private individuals.


Milw electrification - - B&O electrification - - New Haven electrification >

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North East Rails  Clint Chamberlin.
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