PRR Steam Classification

Dick Ross

Notes

Contributors

Comments and corrections by Charles B. Meyer

Duplex vs. Mallet

Rigid frame duplexes are shown thus: 4-4-4-4 [T-1], whereas articulateds are shown as 0-8+8-0 [CC-1]. There were also semipermanently coupled units. True Mallets were compound articulateds which used steam twice (and had two different cylinder sizes, the larger one for the lower pressure second expansion. In simple articulateds, each engine had identically sized cylinders and used steam only once.

Superheating

The letter "s" was appended to the class name to indicate superheated locomotives. However, "s" was used only for those classes whose locomotives originally were not superheated. E.g., the original E6 did not have a superheater. When 51 new E6 locomotives were built with superheaters, they were all classed E6s. The "s" remained even after all locomotives were converted, apparently to indicate the history of the E6 class. Similarly all K4 locomotives were converted to K4s, and the "s" was retained. Classes such as M1, J1, Q2, T1 were superheated right from the start, and no "s" designator was used.

Steam Locomotives

"Simplex" Locomotives

Class Subclasses Wheel
Config. 		Common Name Comments
A A1 .. A5 0-4-0 Switcher j
B B2 .. B8 0-6-0 Switcher
B23 13 locomotives, aquired with Vandalia Lines
B28 30 locomotives, USRA Design - acquired PRR Headlights and Smoke Box Fronts
B29 135 locomotives, Lines West Radial stay design
C C1 0-8-0 Switcher 90 locomotives
D D1 .. D16 4-4-0 American
E E1 4-4-2 Atlantic built as camelback
E2 Lines West design; most converted to E7
E3 Lines West design
E4 .. E6
E7 Lines West design
F F1 .. F3 2-6-0 Mogul
F27s 11 Locomotives acquired with Vandalia
G G1 .. G5 4-6-0 Ten-Wheeler
G34b 8 Locomotives acquired with Grand Rapids & Indianna (GR&I)
H H1 .. H10 2-8-0 Consolidation
I I1 2-10-0 Decapod
J J28 2-6-2 Prairie 2 Alco Experimentals # 7453 (Lines West) #2761 (PRR Co); Lost out to K-4; Class vacated by 1940
J J1 2-10-4 Texas Lima design for C&O, copied by PRR for WW II emergency; note class letter reused from original
K K1 4-6-2 Pacific Designed but never built
K2 .. K4
K5 2 large-boilered experimental locomotives, #5698 & #5699
K21s 12 Locomotives acquired with Vandalia lines
K28 Alco experimental Lines West #7067; test bed for K-2; Scrapped 1933-06.
K29 Alco experimental PRR Co #3395. Test bed for K-4 [some debate on this]. Letter s added 1913-08 to indicate superheating, which was present from beginning. Scrapped 1929-09.
L L1 2-8-2 Mikado
L2s USRA Light Mikado; PRR had more than 100 during WW I; only 5 retained for use on GR&I
M M1 4-8-2 Mountain
M1a
N N1 2-10-2 Santa Fe PRR design
N2 USRA Design; 130 locomotives for Lines West; Delivered with radial stay boilers
N2sa Begining in 1925 all N2 recieved Belpaire firebox boilers and superheaters to become N-2sa

Duplex Locomotives

Class Subclasses Wheel
Config. 		Common Name Comments
Q Q1 4-6-4-4 Duplex Rigid frame; freight type; One of a kind, #6130. Apparently Pennsy considered both Q1 and Q2 to be 4-10-4 for letter classification purposes.
Q2 4-4-6-4 26 locomotives: #6131 & #6175-6199
S S1 6-4-4-6 Duplex "Big Engine" or "World's Fair Engine"; one of a kind, #6100
S2 6-8-6 Turbine Lionel Engine; one of a kind, #6200
T T1 4-4-4-4 Duplex 52 Locomotives: prototypes #6110, 6111; production #5500-5549

Mallet and Articulated Locomotives

Class Subclasses Wheel
Config. 		Common Name Comments
CC CC1 0-8+8-0 Mallet Compound Articulated; one of a kind, #3397
CC2 10 locomotives; Lines West pusher and transfer service
HC HC1 2-8+8-0 Mallet experimental articulated; one of a kind, #3700
HH HH1 2-8+8-0 Mallet experimental Alco articulated; one of a kind, #3396; scrapped
HH1 articulated, 6 locomotives, ex-N&W class Y3 #373-378. PRR class HH-1 re-used for these locomotives; locos given keystone number plates to show PRR ownership.

Electric Locomotives

Class Subclasses Wheel Config. Common Name Comments
B B-1 0-6-0 (switcher)
L L-5 2-8-2
O O-1 4-4-4 Jubilee
P P-5 4-6-4 Baltic; Hudson
R R-1 4-8-4 Northern
BB BB-1 0-6-0+0-6-0 Later separated to become class B-1
DD DD-1 4-4-4-4 With side rods
FF FF-2 2-6+6-2 ex-Milwaukee road 2-6-6-2
GG GG-1 4-6+6-4
Data: Dick Ross VVA249@aol.com
HTML: Mark D. Bej bejm@eeg.ccf.org
1997.10.16