Canadian National Railways Diesel locomotive No.6789, an  FPA-4 at the Monticello Railway Museum.

(aka Kath, CC BY 2.0 <>, via Wikimedia Commons)


Alco-GE logo.


The ALCO FA is a family of B-B diesel locomotives designed to haul freight trains. The locomotives were built by a partnership of ALCO and General Electric (Alco-GE) in Schenectady, New York, between January 1946 and May 1959. Designed by General Electric's Ray Patten (along with their ALCO PA cousins), they were of a cab unit design; both cab-equipped lead (A unit) FA and cabless booster (B unit) FB models were built. A dual passenger-freight version, the FPA/FPB, was also offered. It was equipped with a steam generator for heating passenger cars.

ALCO's designation of F marks these locomotives as being geared primarily for freight use, whereas the P designation of the PA sets indicates that they were geared for higher speeds and passenger use. However, beyond this their design was largely similar - aside from the PA/PB's both being larger A1A-A1A types with an even more striking nose - and many railroads used FA and PA locomotives for both freight and passenger service.

Several examples of FAs and FBs have been preserved. While most are now in the care of railroad museums, a few remain in operational status on such lines as the Cuyahoga Valley Scenic Railroad, Grand Canyon Railway and the Napa Valley Wine Train.


ALCO/GE FA-2 demonstrator locomotive, December 1950. This set was eventually sold to the Chicago and North Western railroad.

(ALCO-GE, Public domain, via Wikimedia Commons)


Service history

Three different models were offered. The FA-1/FB-1, which featured a 1,500 horsepower (1,100 kW) rating, was built from January 1946 to October 1950, with a 1,600 hp (1,200 kW) version produced between March and August 1950 (many early models were subsequently upgraded to 1,600 hp). The 1,600 hp (1,200 kW) FA-2/FB-2 (along with the FPA-2/FPB-2 variants) was built between October 1950 and June 1956. Finally, the 1,800 hp (1,300 kW) FPA-4/FPB-4, powered by the 251 V-12 engine, was built between October 1958 and May 1959 by ALCO's Canadian subsidiary, Montreal Locomotive Works (MLW).

The FAs, as well as their cousins, the ALCO PAs, were born as a result of ALCO's development of a new diesel engine design, the Model 244. In early 1944, development started on the new design, and by November 1945, the first engines were beginning to undergo tests. This unusually short testing sequence was brought about by the decision of ALCO's senior management that the engine and an associated line of road locomotives had to be introduced no later than the end of 1946.

In preparation for this deadline, by January 1946, the first four locomotives with the 244 engines had been built. Two FA-1s and an FB-1 were painted in ALCO Demonstrator colors and were released for road tests for a month and a half on the Delaware and Hudson Railway.

A strike at ALCO delayed production beyond the first four units and the three demonstrator units began working on the Gulf, Mobile, and Ohio Railroad in mid February 1946. The demonstrators were returned to Schenectady when the remainder of the order began delivery in May 1946.

The GM&O order was completed in April 1947 for a total of 80 units. Before the end of this production run, ALCO upgraded the generators and traction motors in the locomotives, with the first of these models entering service in February 1947 for the New York Central.

In 1950, the Montreal Locomotive Works, an affiliate of ALCO, began production of FAs as well. In the fall of 1950, an upgraded model, the FA-2, was launched. This model featured an uprated Model 244 engine, with an output of 1,600 horsepower. Additionally, the carbody was lengthened, making possible the addition of a steam generator in the A unit to allow for use in passenger service. Models equipped as such were designated the FPA-2/FPB-2.

The first FA-2s were delivered in October 1950 to the Baltimore and Ohio and the Erie. By this time, however, the cab unit had fallen out of favor due to the greater versatility of road switchers, and US production of the FA line ended in 1956, with Canadian production ending in 1959.

From the 1970s until 1999, the Long Island Rail Road used 20 FA units converted into "power packs". The traction motors were removed, and original prime movers replaced with 600 horsepower (450 kW) engines/generators solely for supplying Head-end power (HEP). The engineer's control stand was left intact, allowing the engines to be used in push-pull service with other locomotives, which usually lacked HEP. By the late 1990s and early 2000s, the railroad began retiring the ALCOs in favor of new bi-level cab cars and locomotives with HEP installed.


CN FPA4 6769 with the first section of Pool Train 15, The International, at Dorval, QC on September 6, 1965. (Roger Puta, courtesy Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)

Western Maryland Alco FA2 No. 301 at Williamsport, MD on October 4, 1970. (Roger Puta, courtesy Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)


Original production

Units produced by ALCO and the Montreal Locomotive Works (1946–1956)

Almost 800 FA units were built by ALCO and MLW, with just over 15% of them sold to New York Central Railroad, and another 5% each to Union Pacific Railroad, Gulf, Mobile and Ohio Railroad and Missouri Pacific Railroad. About half as many FB units were produced and sold in similar ratios.


FA-1 (cab) and FB-1 (cabless booster) units

Railroad Quantity FA-1 Quantity FB-1 Road numbers FA-1 Road numbers FB-1 Notes
Canadian National Railways 8 9400–9407 Built by MLW
Canadian Pacific Railway 8 4 4000–4007 4400–4403 Built in USA for operations in Vermont
Canadian Pacific Railway 20 20 4008–4027 4404–4423 Built by MLW
Chicago, Rock Island and Pacific Railroad 16 8 145–160 145B–152B Re-engined by EMD
Erie Railroad 22 22 725A,D–735A,D 725B,C–735B,C
Estrada de Ferro Central do Brasil 12 3201–3212 1,600 mm (5 ft 3 in) Irish gauge
Great Northern Railway 8 5 276A,B, 310A,C, 440A,D, 442A,D 310B, 440B,C, 442B,C 440A,B,C,D and 442A,B,C,D to Spokane, Portland & Seattle
Green Bay and Western Railroad 2 503 (1st), 507 503 renumbered 506
Green Bay and Western (Kewanee, Green Bay and Western) 3 501, 502, 503 (2nd)
Gulf, Mobile and Ohio Railroad 55 33 700–754 B1–B33 700,B1,701 were Alco Demonstrators 1500-1502, also purchased Alco static test unit 702 the 3rd FA-1 built
Lehigh and New England Railroad 10 3 701–710 751–753 to Louisville and Nashville 332–341 (A) 327–329 (B) on L&NE abandonment
Lehigh Valley Railroad 10 10 530–548 (even) 531–549 (odd)
Minneapolis, St. Paul and Sault Ste. Marie Railway ("Soo Line") 14 205A,B–211A,B
Soo Line (Wisconsin Central Railway) 8 2220A,B–2223A,B
Missouri-Kansas-Texas Railroad 18 326A,C–334A,C 331A replaced by FA-2; renumbered 82A,C–90A,C
Missouri Pacific Railroad 30 15 301–330 301B–310B, 321B–325B
New York Central Railroad 44 23 1000–1043 3300–3322
New York, New Haven and Hartford Railroad 30 15 0400–0429 0450–0464
Pennsylvania Railroad 8 8 9600–9607 9600B–9607B
Reading Company 6 6 300A–305A 300B–305B
St. Louis-San Francisco Railway 32 16 5200–5231 5300–5315 Most were rebuilt with EMD 567 Prime Movers.
Secretaria de Comunicaciones de Obras Publicas (SCOP) (Mexico) 5 23031–23034, 23039
Seaboard Air Line Railroad 3 3 4200–4202 4300–4302
Spokane, Portland and Seattle Railway 14 8 850A-1,2–860A-1,2, (even) 866A-1,2 856B-1,2–860B-1,2 (even), 866B-1,2 FA's renumbered to 850–867 and FB's to 200–211
Tennessee Central Railway 5 1 801–805 801B
Union Pacific Railroad 44 44 1500A–1523A, 1542A–1543A, 1626–1643 1524B–1541B, 1618B,C–1642B,C (even) 1500A–1523A renumbered 1600A–1623A; 1524B–1541B renumbered 1600B,C–1616B,C (even)
Wabash Railroad 10 5 1200,A–1204,A 1200B–1204B
Totals 445 249

CP No. 4004, an ALCO FA1, at Yard in Chalk River, Ontario on September 6, 1965. (Roger Puta, courtesy Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)

Missouri Pacific Alco FA2 No. 1374 and No. 1386 awaiting disposition at EMD, La Grange, IL on October 6, 1962. (Roger Puta, courtesy Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)


FA-2 (cab) and FB-2 (cabless booster) units

Railroad Quantity FA-2 Quantity FB-2 Road numbers FA-2 Road numbers FB-2 Notes
American Locomotive Company 2 2 1603A,D 1603B,C 1603A,B,C,D sold to Chicago and North Western 4103A,B-4104A,B
Ann Arbor Railroad 14 50,A–56,A 4 units to Wabash Railroad in 1964, remainder traded to EMD on GP35s
Baltimore and Ohio Railroad 28 16 801,A–807,A; 819,A- 837,A (odd) 801X–807X; 819X-837X (odd), 817AX, 837AX
Canadian National Railways 25 15 9408–9456 (even) 9409–9437 (odd) Built by MLW
Canadian Pacific Railway 20 6 4042–4051, 4084–4093 4465–4470 Built by MLW
Canadian Pacific Railway 12 3201–3212
Consolidated Railways of Cuba 12 1600–1605, 1650–1655
Erie Railroad 8 8 736A,D–739A,D 736B,C–739B,C
Ferrocarriles Nacionales de México 18 24 6507A–6522A, 6519A (2nd), 6534A 6507B–6522B, 6519B (2nd), 6528B-6534B
Great Northern Railway 2 2 278-279A 278-279B
Gulf, Mobile and Ohio Railroad 4 B34–B37
Louisville and Nashville Railroad 39 14 300–321, 353–369 200–211, 330–331
Lehigh Valley Railroad 6 2 580–588,592 (even) 581,585 (odd)
Missouri-Kansas-Texas Railroad 1 331A (2nd)
Missouri Pacific Railroad 43 34 331–360, 374-386 331B–335B, 345B–356B, 370B–386B
New York Central Railroad 80 50 1044–1123 3323–3372
New York, New Haven and Hartford Railroad 5 0465–0469
Pennsylvania Railroad 24 12 9608A–9631A 9608B–9630B (even)
Secretaria de Comunicaciones de Obras Publicas (SCOP) (Mexico) 6 7121-8–7121-13
Spokane, Portland and Seattle Railway 2 2 868A-1,2 868B-1,2 FA's to 868–869 FB's to 212–213
Western Maryland Railway 4 301–304
Totals 334 194

An ALCO FA-2 in passenger service on the Long Island Railroad on March 3, 1976. This was the second life for this FA-2, ex PC & NYC No. 1302, having its prime mover de-rated to 600hp, its traction motors removed and its controls modified to support 'pusher' service with a EMD GP-38-2. (Tim Darnell, CC BY-SA 3.0 <>, via Wikimedia Commons)


New York, New Haven and Hartford Alco FA-1, FB-1 and FA-1 three locomotive set at Cedar Hill Engine Terminal on June 5, 1949. Photo by Lawson Hill. (Audio-Visual Designs, Earlton, NY, Public domain, W. Lenheim Collection)

Units produced by ALCO and the Montreal Locomotive Works (1950–1959)

ALCO and MLW built 152 of the various FP models with the largest quantity, 38% of the total production, sold to Canadian National Railway.


FPA-2 (cab) and FPB-2 (cabless booster) units

Railroad Quantity FPA-2 Quantity FPB-2 Road numbers FPA-2 Road numbers FPB-2 Notes
Baltimore and Ohio 10 5 809,A-817,A (odd) 809X-817X (odd)
Canadian National Railways 6 6 6706–6711 6806–6811 2 A and 2 B units rebuilt to 2 FPA4M and 2 FPB4M in 1955, Built by MLW. Two FPA-2 rebuilt as FPB-2U were 6758 and 6759. 6758 previously numbered as 6755 and delivered new as FPA-2 6711. 6759 previously 6751 and delivered new as FPA-2 6707. FPB-2U transferred to VIA Rail. Retired by VIA in 1987, 6758 is still used by New York and Lake Erie Railroad.
Canadian Pacific Railway 7 2 4082–4083, 4094–4098 4463–4464 Built by MLW
Ferrocarriles Nacionales de México 18 10 6500–6501, 6502A–6506A, 6523A–6533A 6502B–6506B, 6523B–6527B built by Alco and MLW
Ferrocarril del Pacifico 4 901–904 Built by Alco
Great Northern Railway 2 277A,B
Lehigh Valley Railroad 2 2 590, 594 583, 587 594 and 583 were used to field test the new 12V-251 engines in 1954-55
Louisville and Nashville Railroad 5 350–352, 383–384
Missouri Pacific Railroad 19 6 361–373, 387–392 387B–392B
Totals 73 33
Totals 334 194

FPA-4 (cab) and FPB-4 (cabless booster) units

Railroad Quantity FPA-4 Quantity FPB-4 Road numbers FPA-4 Road numbers FPB-4 Notes
Canadian National Railways 34 12 6760–6793 6860–6871 Built by MLW. All transferred to VIA Rail. Few MLW FPA-4 units sold privately to US
Totals 34 12

A pair of MLW FPA-4s on the Napa Valley Wine Train.

(Drew Jacksich from San Jose, California Republic, CC BY 2.0 <>, via Wikimedia Commons)


Surviving examples

Some 20 units of various designations exist today in a preserved state. Several excursion railways own operating examples which are in regular service, including MLW units received from Via Rail Canada.

  • The Grand Canyon Railway owns 3 FPA-4s, and two FB-1s.
  • The Napa Valley Wine Train owns 4 FPA-4s.
  • The Cuyahoga Valley Scenic Railroad in Peninsula, Ohio, owns four FPA-4s, of which three are in operation as of 2008.
  • The New York and Lake Erie Railroad owns one FPA-2 and one FPA-4. Ex-CN/VIA Rail 6758 was FPA-2 but rebuilt and is now a FPA-2U.

Locomotives not sold to tourist railroads have been sold to museums and other owners.

  • The Illinois Railway Museum owns former Louisville & Nashville FA-2 No. 314.
  • The Western Maryland Railway Historical Society owns former Western Maryland FA-2 No. 302.
  • The Railroad Museum of New England owns former New York, New Haven, & Hartford FA-1 No. 0401.
  • A private group in Buffalo, New York owns a former New York Central FA-2, No. 1102.
  • Spokane, Portland and Seattle Railway FA-1 No. 866 is undergoing restoration by a private owner in Portland, Oregon.
  • Spokane Portland & Seattle FB-1 868B is owned by a private owner in NJ.
  • The Canadian Railway Museum in Delson, Quebec owns CN FPA-4 No. 6765 and CN FA-1 No. 9400.
  • The Danbury Railway Museum owns an FPA-4 and FPB-4. They have been restored as Canadian National FPA-4 6786 and FPB-4 No. 6867. Also at the Danbury Railway Museum is ex-New Haven FA-1 0428.
  • The Monticello Railway Museum houses privately owned CN 6789, an MLW FPA-4, and CN 6862, an MLW FPB-4. The A-B set was restored into operating condition and CN 6789 is used on museum trains. Both have been repainted into the green/yellow scheme that CN used early on.
  • Canadian Pacific FA-2 4090 and FB-2 4469 survive as static displays at the Canadian Museum of Rail Travel.
  • The Anthracite Railroads Historical Society owns former Louisville & Nashville FA-2 No. 315.
  • Western Maryland FA-2 No. 303 is stored in Barton, MD on the Georges Creek Railway. It was recently sold to a railroad shop in Kansas City.
  • Canadian National 6854 is owned by a private owner in Bridgeton, NJ.
  • Canadian National 6783 has recently moved to Tennessee.


Alco "World Locomotive"

Alco built 23 A1A-A1A trucked FCA-3s for Pakistan Railways in 1951 and 1953. These were the equivalent of an FPA-2 riding on A1A trucks. ALCO's "World Locomotive", the DL500 (introduced in 1953), originated as a newly designed demonstrator based on the FA-2. The first 25 DL500s used the model 244 engine rated at 1,600 horsepower (1,200 kW). Later DL500s were like the FPA-4 and utilize the ALCO model 251B diesel engine as the prime mover and are rated at 1,800 horsepower (1,300 kW). All DL500s were built with C-C trucks, but B-B or paired A-1-A trucks were offered as an option. The only locale within the Americas where ALCO-built cab units, such as All America Latina Logistica (ALL), still see daily usage in freight duty is Argentina. A total of 369 DL500 locomotives were built by ALCO, AE Goodwin, and MLW between May 1953 and December 1967.

Variants of the ALCO "World Locomotive" saw service in Australia, where it was built under license by AE Goodwin, Sydney. Six single-cab locomotives were delivered to the South Australian Railways (SAR) in 1955 as the 930 class. In 1957, the SAR received the first of an eventual 31 built to a two-cab design, the end with the second cab being flat-fronted. A few months later, the first of an up-rated version of the two-cab design arrived on the Department of Railways New South Wales as the 44 class, of which 100 were in service by 1968.

For more information regarding Alco locomotives built for foreign use, click HERE.


ALCO FA and FB Overview

Type and origin
Power type: Diesel-electric
Builders: Partnership of American Locomotive Company (ALCO) and General Electric (GE); Montreal Locomotive Works
Model FA-1, FB-1, FA-2, FB-2, FPA-2, FPB-2, FCA-3, FPA-4, FPB-4
Build date: January 1946 – May 1959
Total produced: 1,401
​• AAR B-B, A1A-A1A (FCA-3 only)
• UIC Bo′Bo′
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Length FA-1: 51 ft 6 in (15.70 m)
Length FB-1: 50 ft 2 in (15.29 m)
Length FA-2, FPA-2, FPA-4: 53 ft 6 in (16.31 m)
Length FB-2, FPB-2, FPB-4: 52 ft 8 in (16.05 m)
Locomotive weight FA-1/FB-1, FA-2/FB-2, FPA-2/FPB-2: 243,000 lb (110,000 kg)
Locomotive weight FPA-4/FPB-4: 255,000 lb (115,666.1 kg)
Fuel capacity: 1,200 US gal (4,500 L; 1,000 imp gal)
Prime mover FA-1/FB-1, FA-2/FB-2, FPA-2/FPB-2: ALCO 244
Prime mover FPA-4/FPB-4: ALCO 251
Engine type: V-12 Four-stroke diesel
Aspiration: Turbocharger
Displacement: 8,016 cu in (131.36 L)
Generator: DC generator
Traction motors: DC traction motors GE 726 on GM&O initial order then GE 752
Cylinders: 12
Cylinder size: 9 in × 10.5 in (229 mm × 267 mm)
Transmission: Electric
Locomotive brake: Independent air. Optional: Dynamic
Train brakes: Air
Performance figures
Maximum speed: 65–75 mph (105–121 km/h)
Power output Early FA-1/FB-1: 1,500 hp (1,100 kW)
Power output Late FA-1/FB-1 & all FA-2/FB-2/FPA-2/FPB-2: 1,600 hp (1,200 kW)
Power output FPA-4/FPB-4: 1,800 hp (1,300 kW)
Tractive effort: FA-1/FB-1, FA-2/FB-2, FPA-2/FPB-2: 60,875 lbf (270.79 kN)
Tractive effort: FPA-4/FPB-4: 63,750 lbf (283.57 kN)
Locale: North America, Brazil, Pakistan, México
Disposition: Many preserved, some under restoration, rest scrapped.