6× 625hp (466kW) AC motors;[2][4] plus 4× 375hp (280kW) motors on the trucks on P5b[3]
Transmission
AC current fed via transformer tap changers to paired motors geared (25:97) to quill drives on each driving axle;[2][4] plus single motors geared to driving axles on end trucks on P5b (gear ratio: 17:50)[3]
The first P5s were built with box cabs. A grade crossing accident in which the crew were killed led to the substitution of a central cab to give better crash protection, a streamlined steeple type, in later production, a design which was also applied to the GG1.
More information Year, Builder ...
Table of P5 locomotive production
Year
Builder
Bodystyle
Road numbers
Notes
1931
Altoona
Boxcab
7898-7899
Class P5, Renumbered 4700 & 4791 respectively in 1933
1932
Westinghouse
4701–4732
4702 rebuilt to P5b in 1937
General Electric
4755–4774
4770 rebuilt as Modified in 1945
1933
Westinghouse
4733-4742
1934
Altoona
Modified
4780
1935
Westinghouse
4743–4754
General Electric
4775-4779
Altoona
4781-4790
Close
When the GG1s were put in passenger service, the P5s were regeared and used in freight service for many years. The last of the class was withdrawn from service in April 1965.[5]
P5 prototypes
Two prototype locomotives were outshopped from the PRR's Altoona Works in 1931.[1] They were essentially the PRR's 2-B-2 O1 design lengthened by adding another pair of driving wheels; while the O1 was an "electric Atlantic" equivalent to the E6s steam locomotive, the P5 was an "electric Pacific" designed to match or better the performance of the PRR's ubiquitous K4s Pacifics.
These prototypes had electrical equipment from both Westinghouse and General Electric; the design was by both companies and the PRR's electrical department, and the equipment from each manufacturer was identical.
P5a production locomotives
Orders were placed for 90 production locomotives classified P5a due to minor changes from the prototypes (notably, larger traction motor blowers).[1] Production was split between General Electric and Westinghouse; the GE examples were assembled at GE's Erie, Pennsylvania facility, still a locomotive assembly plant today, while final assembly for the Westinghouse order was subcontracted to the Baldwin Locomotive Works.
P5a (modified) steeplecabs
A fatal grade crossing accident on the New York Division confirmed traincrews' concerns about safety when the crew were killed after colliding with a truckload of apples.[1] A redesign was undertaken, giving the locomotives a central cab, raised higher, with narrower-topped, streamlined "noses" to the locomotive to enable the crew to see forward. The final 28 locomotives were built to this design, which was not given a separate class designation since it was mechanically and electrically identical; they were called class P5a (modified), and colloquially Modifieds.[1]
Documentation published in 2010 disproved the decades long belief that the modified P5's new shell design came first and was then applied to the GG1, R1, and eventually the DD2. Instead, it was revealed that the GG1 project, under the direction of industrial designer Donald R. Dohner, was the first to receive the center cab design, and that soon afterward it was applied to the R1 and P5.[6]
The Modified units (along with the R1 and prototype GG1) were built with riveted carbodies. However, unit #4770, rebuilt to a Modified appearance in January 1945 after being wrecked in February 1944,[7][8] differed from previous Modifieds in having an all-welded carbody, the type of construction famously utilized in the production run of the GG1.[9]
P5b experiment
In October 1937, P5a #4702 was rebuilt with motors in its trucks to become the only locomotive in subclass P5b. Each truck axle was given a 375-horsepower (280kW) motor,[3] adding 1,500hp (1,100kW) to give a total power output of 5,250hp (3,910kW) and a wheel arrangement of B-C-B or Bo′CoBo′. The main drivers had used double traction motors[de] on each axle, but the trucks were a single motor per axle. This modification also meant that locomotive's entire weight was carried on driven wheels. Despite these advantages the experiment was not repeated, however #4702 continued in its modified form.
Visually, the class P5b could be distinguished from a boxcab P5a by having a lower row of ventilation grilles on the sides of the superstructure, and by having outside brake cylinders on the trucks.[1]
Staufer, Alvin F.; Pennypacker, Bert (1962). Pennsy Power: Steam and Electric Locomotives of the Pennsylvania Railroad, 1900-1957. Research by Martin Flattley. Carollton, Ohio: Alvin F. Staufer. p.298. ISBN978-0-9445-1304-0.
Interstate Commerce Commission. Investigation no. 2774 The Pennsylvania Railroad Company report in re accident near Roxton, Pa., on February 13, 1944. OCLC947002343.
Volkmer, William D. (1991). Pennsy Electric Years. Edison, New Jersey: Morning Sun Books. pp.26–27. ISBN1-878887-01-7.
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