PRR locomotive classification

Locomotive classification on the Pennsylvania Railroad took several forms. Early on, steam locomotives were given single-letter classes. As the 26 letters were quickly assigned, that scheme was abandoned for a more complex system.[1] This was used for all of the PRR's steam locomotives, and with the exception of the final type bought (the E44) all electric locomotives also used this scheme.

PRR steam and electric classification

A: 0-4-0

Class A was the 0-4-0 type, an arrangement best suited to small switchers. Most railroads abandoned the 0-4-0 after the 1920s, but the PRR kept it alive for use on small industrial branches, especially those with street trackage and tight turns.

B: 0-6-0

Class B comprised the 0-6-0 type, the most popular arrangement for switchers on the PRR.

C: 0-8-0

Class C was assigned to the 0-8-0 type. These were very common on other railroads, but the PRR was not keen on them and only built a few. This was partly because the PRR used 2-8-0 "Consolidation" types for similar service.

D: 4-4-0

Class D was the 4-4-0 "American" type, the most common arrangement in 19th Century American railroading. 4-4-0s stayed in service on the PRR in secondary work later than on most other railroads, and three were in use until after World War II

E: 4-4-2

The 4-4-2 "Atlantic" type was assigned class E. The PRR was an enthusiastic user of the Atlantic type in flatter country, and built some of the most advanced Atlantics used in the United States.

F: 2-6-0

The 2-6-0 "Mogul" type was assigned class F. On the PRR, this type was used during the period of 18951925, approximately. They were mostly used to haul express freight, although some hauled suburban passenger trains.

G: 4-6-0

H: 2-8-0

I: 2-10-0

The 2-10-0 "Decapod" type was assigned class I. The PRR only owned one type of Decapod, class I1s, but they owned 598 of them, one of the largest classes of identical power in the United States.

J: 2-6-2 and 2-10-4

Class J was first used for two experimental 2-6-2 "Prairie" locomotives built by ALCO in 1905. These were both withdrawn from service by the mid-1920s. In 1942, the PRR built 250 2-10-4 "Texas" type locomotives based on C&O plans; class J now being unoccupied, it was reused for them. The PRR J1 was an improved version of its C&O counterpart with more pulling power.

K: 4-6-2

The PRR assigned class K to the 4-6-2 "Pacific" type. The Pacific was the most common type of passenger locomotive on the Pennsylvania.

L: 2-8-2

Class L was assigned to the 2-8-2 "Mikado" type.

M: 4-8-2

N: 2-10-2

O: 4-4-4

The 4-4-4 arrangement was rare anywhere, and on the PRR it was found only on eight experimental electric locomotives.

P: 4-6-4

The 4-6-4 arrangement was seen on the PRR only on electric locomotives. As a steam locomotive arrangement, it was poorly suited to the PRR's mountainous terrain, wasting much potential adhesive weight on non-driven wheels. That it was so widely used by the rival New York Central would also likely have factored against PRR adoption.

Q: 4-4-6-4 or 4-6-4-4

The Q class comprised what were effectively 4-10-4s with the driving axles split into two driven groups. The Q2 was the most powerful non-articulated steam locomotive ever built and also holds the record for highest horsepower recorded by any steam locomotive at 7,987 hp.

R: 4-8-4

The PRR never built any steam locomotives of the 4-8-4 "Northern" type, although the T1 duplexes were effectively a "Northern" with the driving wheels split into two groups.

S: 6-4-4-6 or 6-8-6

Both S class locomotives were originally intended to only have four leading and trailing wheels, but increases in weight required them. In the case of the S2, it was due to wartime limits on the use of advanced steel alloys.

T: 4-4-4-4

The duplex-drive T1 was the final class of steam locomotive constructed for the Pennsylvania Railroad, and possibly the most controversial.

Compound classifications

The PRR classified articulated locomotives and joined locomotive units by using multiples of the previous classifications.

Articulated steam:

Articulated electric:

Non-standard electric classification

The horsepower-based designation unique to the E44 would be retained and expanded by Penn Central to cover the former New Haven EF4s (E33) and EP5s (E40).

Diesel classification[1]

The Pennsylvania Railroad was slow to dieselize. By the end of WW2 they only had 18 units. However over the next 22 years they had acquired a total of 3005 units.[1] They bought from all the manufacturers: Alco 516 units, Baldwin 643 units, EMD 1,479 units, Fairbanks-Morse 200 units, General Electric 145 units, and Lima 22 units. This diversity was a nightmare for the maintenance department as there was very little compatibility amongst the different builders.

The class number system is as follows:
The first letter stood for the manufacturer; A=Alco, B =Baldwin, G =General Electric, E =EMD, F =Fairbanks-Morse, and L =Lima.
The second and third letters represented the type of service; S =switcher, F =Freight, P =passenger, :: PF=dual service, RS =road-switcher, and H =helper.
The next number(s) were for horse power rounded to hundreds.
The last letter, if used, was for model variations.

Alco

PRR ClassBuilder’s ModelBuild dateTotal
produced
Wheel
arrangement
ServicePower outputNotes
AS6 S-1 1947–1951 40 B-B Switcher 600 hp (450 kW)
AS10 S-2 1948–1954 90 B-B Switcher 1,000 hp (750 kW) 22 units MU class AS10m
AS10a T-6 1958 6 B-B Switcher 1,000 hp (750 kW)
AF15 FA-1 1948–1950 8 B-B Freight 1,500 hp (1,120 kW)
AF15 FB-1 1948–1950 8 B-B Freight 1,500 hp (1,120 kW)
AF16 FA-2 1951 24 B-B Freight 1,600 hp (1,190 kW)
AF16 FA-2 1951 12 B-B Freight 1,600 hp (1,190 kW)
AFP20 PA-1 1947 10 A1A-A1A Pass 2,000 hp (1,490 kW) many converted to Freight
AFP20 PB-2 1947 5 A1A-A1A Pass 2,000 hp (1,490 kW) many converted to Freight
ARS10 RS-1 1948–1952 27 B-B Freight 1,000 hp (750 kW) 5 units used in Pass service
ARS15 RS-2 1948 6 B-B Freight 1,500 hp (1,120 kW) ex D&H
ARS16 RS-3 1951–1955 115 B-B Freight 1,600 hp (1,190 kW) 45 units used in Pass service
ARS16a RSD-4 1952–1953 6 C-C Freight 1,600 hp (1,190 kW)
ARS18 RS-11 1956–1957 32 B-B Freight 1,800 hp (1,340 kW)
ARS18a RS-12 1957–195825 C-C Freight 1,800 hp (1,340 kW)
ARS20 RS-11 1956–1957 6 B-B Freight 2,000 hp (1,490 kW)
ARS24 RSD-15 1956 6 C-C Freight 2,400 hp (1,790 kW)
ARS24s RSD-7 1955–1956 5 C-C Pass 2,400 hp (1,790 kW)
ARS24 RS-27 1962 15 C-C Freight 2,400 hp (1,790 kW)
AF24 C-424 1962 1 C-C Freight 2,400 hp (1,790 kW)
AF25 C-425 1964–196531 C-C Freight 2,500 hp (1,860 kW)
AF27 C-628 1965 15 C-C Freight 2,750 hp (2,050 kW)
AF30 C-630 1966 15 C-C Freight 3,000 hp (2,240 kW)

Baldwin Locomotive Works

PRR ClassBuilder’s ModelBuild dateTotal
produced
Wheel
arrangement
ServicePower outputNotes
BS6 VO-660 1942–1945 12 B-B Switcher 600 hp (450 kW)
BS6 DS-4-4-660 1942–1945 99 B-B Switcher 660 hp (490 kW)
BS7 DS-4-4-750 1951 24 B-B Switcher 750 hp (560 kW)
BS7 S8 1951 7 B-B Switcher 750 hp (560 kW)
BS10 VO 1943–1945 8 B-B Switcher 1,000 hp (750 kW)
BS10 DS-4-4-1000 1948–1950 137 B-B Switcher 1,000 hp (750 kW)
BS12 S-12 1951–1956 98 B-B Switcher 1,200 hp (890 kW)
BF15 DR-4-4-1500 1940–1950 34 B-B Freight 1,500 hp (1,120 kW) Cab (A) aka “Sharknose
BF15 DR-4-4-1500 1940–1950 34 B-B Freight 1,500 hp (1,120 kW) Cab (B)
BF16 RF-16 (A) 1950–1952 72 B-B Freight 1,600 hp (1,190 kW) Cab (A) aka “Sharknose
BF16 RF-16 (B) 1950–1952 30 B-B Freight 1,600 hp (1,190 kW) Cab (B)
BP60a DR-12-8-3000 1947–1948 24 2-D-D-2 Pass 3,000 hp (2,240 kW) converted to helper aka "Centipede"
BP20 DR-6-4-2000 1948 18 A1A-A1A Pass 2,000 hp (1,490 kW) Cab (A)
BP20 DR-6-4-2000 1948 9 A1A-A1A Pass 2,000 hp (1,490 kW) Cab (B)
BRS10 DRS-4-4-1000 1949–1950 6 B-B Pass 1,000 hp (750 kW)
BRS12 RS-12 1951–1954 8 B-B Pass 1,200 hp (890 kW) 3 units used in Pass service
BRS15 DRS-4-4-1500 1950 8 B-B Pass 1,500 hp (1,120 kW)
BRS16 AS-616 1953–1955 28 C-C Pass 1,600 hp (1,190 kW) 16 units used in Pass service
BRS24 RT-624 1951–1954 22 C-C Transfer 2,400 hp (1,790 kW)
LRS25 T2500 1950–1951 22 C-C Transfer 2,500 hp (1,860 kW) Built by Lima Locomotive Works

General Electric

PRR ClassBuilder’s ModelBuild dateTotal
produced
Wheel
arrangement
ServicePower outputNotes
GS4 44 Ton 1948–1950 46 B-B Switcher 400 hp (300 kW)
GF25 U25B 1965 59 B-B Freight 2,500 hp (1,860 kW)
GF25a U25C 1965 20 C-C Freight 2,500 hp (1,860 kW)
GF28a U28C 1966 15 C-C Freight 2,800 hp (2,090 kW)
GF30a U30C 1967 5 C-C Freight 3,000 hp (2,240 kW)

EMD

PRR ClassBuilder’s ModelBuild dateTotal
produced
Wheel
arrangement
ServicePower outputNotes
ES6 SW 1937 12 B-B Switcher 600 hp (450 kW)
ES6 SW1 1942–1950 85 B-B Switcher 600 hp (450 kW)
ES10 NW2 1941–1948 32 B-B Switcher 1,000 hp (750 kW)
ES12 SW7-SW9 1950–1953 84 B-B Switcher 1,200 hp (890 kW)
ES12 SW1200 1957 35 B-B Switcher 1,200 hp (890 kW)
EF15 F3A,F7A 1947–1952 203 B-B Freight 1,500 hp (1,120 kW) Cab A unit
EF15 F3B,F7B 1947–1952 107 B-B Freight 1,500 hp (1,120 kW) Cab B unit
EPF15 FP7A 1952 40 B-B Pass 1,500 hp (1,120 kW) Cab A unit
EPF15 FP7B 1952 14 B-B Pass 1,500 hp (1,120 kW) Cab B unit
EP20 E7A 1945–1949 46 A1A-A1A Pass 2,000 hp (1,490 kW) Cab A unit
EP20 E7B 1945–1949 14 A1A-A1A Pass 2,000 hp (1,490 kW) Cab B unit
EP22 E8A 1950–195274 A1A-A1A Pass 2,250 hp (1,680 kW) Cab A unit
ERS15 GP7 1952–195366 B-B Freight 1,500 hp (1,120 kW) 10 units used in Pass service
ERS15ax SD7 19532 B-B Freight 1,500 hp (1,120 kW)
ERS17 GP9 1955–1959310 B-B Freight 1,750 hp (1,300 kW) 40 units no cab
ERS17a SD9 1957–195825 C-C Freight 1,750 hp (1,300 kW)
EF22 GP30 196352 B-B Freight 2,250 hp (1,680 kW)
EF25 GP35 1964–1965119 B-B Freight 2,500 hp (1,860 kW)
EF25a SD35 196540 C-C Freight 2,500 hp (1,860 kW)
EF30a SD40 196665 C-C Freight 3,000 hp (2,240 kW)
EF36 SD45 196665 C-C Freight 3,600 hp (2,680 kW)
EF20a GP38 19675 B-B Freight 2,000 hp (1,490 kW) Built for PRSL

Fairbanks-Morse

PRR ClassBuilder’s ModelBuild dateTotal
produced
Wheel
arrangement
ServicePower outputNotes
FS10 H10-44 1948–1949 55 B-B Switcher 1,000 hp (750 kW)
FS12 H12-44 1952–1954 16 B-B Switcher 1,200 hp (890 kW)
FF20 Erie Built 1947–1948 36 A1A-A1A Freight 2,000 hp (1,490 kW) Cab A
FF20 Erie Built 1947–1948 12 A1A-A1A Freight 2,000 hp (1,490 kW) Cab B
FF16 CF-16-4 1950 16 B-B Freight 1,600 hp (1,190 kW) Cab A
FF16 CF-16-4 1950 8 B-B Freight 1,600 hp (1,190 kW) Cab B
FRS-16 H16-44 1952 10 B-B Freight 1,600 hp (1,190 kW)
FRS-20 H20-44 1948–1951 38 B-B Freight 2,000 hp (1,490 kW)
FRS-24 H24-66 1953–1954 9 C-C Freight 2,400 hp (1,790 kW) aka Train Master

References

  1. 1.0 1.1 1.2 Staufer, Alvin F., Edson, D. William, and Harley, E. Thomas. Pennsy Power lll. Staufer. ISBN 0-944513-10-7