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FM's "H12-44": Its Most Successful In The Hood Line


Last revised: July 19, 2023

By: Adam Burns

The H12-44 was Fairbanks Morse's most successful diesel locomotive, with nearly 400 constructed over an eleven year period.

While FM featured an opposed-piston prime mover that some railroads found complicated, the company's products were nevertheless rugged machines and quite reliable when understood by maintenance personnel.

This particular model looked quite similar to its predecessor, the H10-44, save for a slight increase in horsepower. While FM was able to sell a number of diesels through its Canadian Locomotive Company arm, it had difficulty finding sales in Mexico and outside of North America.

As it turned out, the H12-44 had one of the longest production runs of any FM model and so many were produced that at least sixteen domestic examples remain preserved today.


26230520582346237426384978908.jpgMilwaukee Road H12-44 #718 is seen here carrying out switching chores in Milwaukee in May, 1969. This unit was built as #1836 in November, 1951 and repainted into Union Pacific's "Armour Yellow" passenger scheme in July, 1964. Fred Byerly photo. American-Rails.com collection.


The H12-44 began production during May of 1950 following the earlier H10-44. Railroads liked this switcher and were even happier with the additional 200 horsepower found in its successor.

The H12-44 was equipped with Fairbanks-Morse's standard 2-cycle, 38D8 1/8 opposed piston prime mover that could produce 1,200 horsepower using B-B trucks.

The carbody styling was again inspired by noted industrial designer Raymond Loewy.  However, to reduce production costs, FM simplified the design in the fall of 1952 removing many of the styling features Loewy had suggested.

It did not really take away from the model's attractiveness although the locomotive did sport a more basic, boxy appearance.

The FM H12-44 carried roughly the same tractive effort as its predecessor, and similar models in production by Alco and Electro-Motive.

Santa Fe H12-44TS #541 and #542 carry out switching chores at Chicago's Dearborn Station in the early 1960s. Note the clock tower of Baltimore & Ohio's Grand Central Station in the background. American-Rails.com collection.

Thanks to the locomotive's relatively light-weight the H12-44 was ideal for use in both yard/switcher service and could also be used in light freight service with its respectable horsepower rating. 

FM's classification system somewhat resembled Baldwin's initial system, although somewhat more simplified. In regards to the H12-44:

  • "H" stood for Hood

  • 12" was for 1,200 horsepower

  • Each 4 meant four axles and four traction motors
Southern Pacific H12-44 #2351 carries out switching work at San Francisco's 3rd & Townsend Depot in May, 1973. Author's collection.

Overall the locomotive sold 320 units domestically in the U.S. and Mexico (1), and another 30 were built by subsidiary Canadian Locomotive Company (CLC) of Kingston, Ontario.

The Santa Fe certainly liked the switcher as the company wound up with 59 examples employing them heavily in light duty work. 

The AT&SF also acquired three additional variants, the H12-44TS for terminal service at Dearborn Station (mentioned in greater detail below)

Generally, FM models sold relatively poorly although it is not necessarily because Fairbanks Morse's design was unreliable as historical texts often mention.

Once the FM O-P engine was well understood by maintenance departments it was quite reliable in service.

For instance, in regards to the H24-66 "Train Master," it has been noted by John Kirkland in his book The Diesel Builders Volume 1 that the locomotives performed admirably for more than 20 years on the Southern Pacific.

960102941825723889830389723087.jpgSanta Fe H12-44 #546 leads a string of cars into Argentine Yard during the 1960s. The Kansas City skyline can be seen in the background. American-Rails.com collection.

This was due to a maintenance team that understood the model, despite taking a daily beating in freight service (and later in commuter assignments around the Bay Area).

In any event, the H12-44 was purchased by a little more than a dozen Class I systems including industries Ayrshire Collieries, U.S. Steel - Fairless Works, Yankeetown Dock, and the Tennessee Valley Authority.

Even the U.S. Army bought the locomotive, 20 to be exact! FM's Canadian arm also built 30 for Canadian National Railway as well as an A1A-A1A design known as the H12-46. CN ultimately wound up with 30 examples of the variant built during the early 1950s.

6801041761761788929060308409.jpgSt. Louis-San Francisco Railway H12-44 #285 is seen here in Tulsa, Oklahoma, circa 1965. The Frisco owned 4 such units, acquired in 1951. Mac Owen photo.

Data Sheet and Specifications

Entered Production5/1950 (Milwaukee Road #1826-1827)
Years Produced5/1950 - 3/1961
Fairbanks-Morse ClassH12-44
Engine38D8 1/8, 6-cylinder Opposed-Piston
Engine BuilderFairbanks-Morse
Carbody StylingRaymond Loewy
Length (Inside Couplers)48' 10"
Height (Top Of Rail To Top Of Cab)14' 6"
Width10' 2"
Weight240,000 Lbs
Truck TypeGSC Rigid Bolster, Drop-Side Equalizer
Truck Wheelbase8'
Wheel Size40"
Traction Motors362D (4), Westinghouse
Traction Generator481F, Westinghouse
Auxiliary GeneratorYG42A, Westinghouse
MU (Multiple-Unit)Yes
Gear Ratio68:14
Tractive Effort34,000 Lbs at 9 mph
Top Speed60 mph

Production Rosters


Total Built = 306

Owner Road Number Construction Number Contract Number Completion Date Quantity
Milwaukee Road1826-182712L374-12L375LD955/19502
Chicago & North Western1071-107212L376-12L377LD945/19502
New York Central911112L378LD9411/19501
New York Central9112-911812L379-12L385LD9212/19507
New York Central9119-912012L386-12L387LD921/19512
Santa Fe503-50412L388-12L389LD979/19502
Santa Fe505-50612L390-12L391LD9710/19502
Baltimore & Ohio310-31912L392-12L401LD1032/195110
Kentucky & Indiana Terminal Railroad60-6112L402-12L403LD1113/19512
Kentucky & Indiana Terminal Railroad62-6412L404-12L406LD1114/19513
Minnesota Western Railroad (Minneapolis, Northfield & Southern)1012L427LD1041/19511
Milwaukee Road1828-183212L428-12L432LD1083/19515
St. Louis-San Francisco Railway (Frisco)282-28512L433-12L436LD1096/19514
Weyerhaeuser Timber Company112L437LD1128/19511
Santa Fe50712L438LD11611/19511
Santa Fe50812L439LD11610/19511
Santa Fe509-51412L440-12L445LD11611/19516
Santa Fe515-51612L446-12L447LD1162/19522
Milwaukee Road1833-183512L448-12L450LD11710/19513
Milwaukee Road1836-183712L451-12L452LD11711/19512
Milwaukee Road1838-184712L520-12L529LD12111/195110
Milwaukee Road2300-230412L561-12L565LD1273/19525
Milwaukee Road2305-230912L566-12L570LD1274/19525
U.S. Steel (Fairless Works)GE912L571LD12811/19511
U.S. Steel (Fairless Works)GE1012L572LD12812/19511
U.S. Steel (Fairless Works)GE11-GE1612L573-12L578LD1282/19526
Santa Fe517-51812L599-12L600LD1317/19522
Santa Fe519-52612L601-12L608LD1318/19528
Santa Fe527-53012L609-12L612LD1319/19524
New York Central9121-912812L613-12L620LD1325/19528
New York Central9129-913712L621-12L629LD1326/19529
Soo Line31512L636LD1346/19521
Indianapolis Union Railway19-2112L650-12L652LD14210/19523
Southern Pacific1486-149012L653-12L657LD1409/19525
Southern Pacific149112L658LD14010/19521
U.S. Army1843-185212L667-12L676LD1361/195310
U.S. Army1853-185512L677-12L679LD1362/19533
U.S. Army1856-185712L680-12L681LD1361/195310
U.S. Army1858-1856212L682-12L686LD1362/19535
Chicago & North Western1110-111312L709-12L712LD13812/19524
Kentucky & Indiana Terminal Railroad6512L719LD1412/19531
Kentucky & Indiana Terminal Railroad6612L720LD1413/19531
New York, Chicago & St. Louis (Nickel Plate Road)134-13812L721-12L725LD1433/19535
Central Of Georgia Railway315-31812L726-12L729LD1463/19534
Wabash Railroad384-38612L744-12L746LD1483/19533
Santa Fe531-54012L747-12L756LD1494/195310
Southern Pacific1529-153512L760-12L766LD1545/19537
Chicago & North Western1114-111612L768-12L770LD1528/19533
Southern Pacific1536-153812L771-12L773LD1548/19533
Baltimore & Ohio196-19712L774-12L775LD1579/19532
Fairbanks-Morse (Demo)*7612L776LD1668/19531
Sandersville Railroad10012L777LD1598/19531
Tennessee Valley Authority2212L778LD17311/19541
Milwaukee Road2310-231412L823-12L827LD1612/19545
Southern Pacific1568-157112L833-12L836LD1861/19564
Milwaukee Road2315-232212L949-12L956LD1751/19558
Milwaukee Road2323-232512L957-12L959LD1752/19553
Soo Line316-31912L965-12L968LD17612/19544
Southern Pacific1572-157312L976-12L977LD1861/19562
Southern Pacific157412L978LD1862/19561
Texas & New Orleans (Southern Pacific)119-12012L979-12L980LD1862/19562
Santa Fe544-54912L1006-12L1011LD18712/19556
Santa Fe550-55112L1012-12L1013LD1872/19562
Santa Fe552-55512L1014-12L1017LD1873/19564
Santa Fe556-55812L1018-12L1020LD1874/19563
Santa Fe541-543**12L1021-12L1023LD1885/19563
Yankeetown Dock212L1024LD1965/19561
Columbia & Cowlitz Railway (Weyerhaeuser)D212L1025LD1955/19561
Southern Pacific1577-158412L1062-12L1069LD20110/19568
Southern Pacific1585-158612L1070-12L1071LD20111/19562
Southern Pacific1587-159412L1072-12L1079LD2051/19578
Southern Pacific1595-159612L1080-12L1081LD2052/19572
New York, Chicago & St. Louis (Nickel Plate Road)139-14512L1082-12L1088LD2063/19577
Baltimore & Ohio9722-972612L1089-12L1093LD2134/19575
Santa Fe559-56012L1094-12L1095LD2073/19572
Santa Fe561-56412L1096-12L1099LD2074/19574
Ayrshire Collieries112L1100LD20811/19581
New York, Chicago & St. Louis (Nickel Plate Road)146-15112L1101-12L106LD2153/19586
New York, Chicago & St. Louis (Nickel Plate Road)152-15512L1107-12L110LD2154/19584
Ferrocarril Chihuahua al Pacífico (Chihuahua-Pacific Railway)7012L111LD218-33/19611

*  Became Yankeetown Dock Corporation #1.

** These were H12-44TS variants.

Canadian Locomotive Company

Total Built = 30

Owner Road Number Construction Number Completion Date Quantity
Canadian National1630-16322880-28828/19553
Canadian National1633-16352883-28859/19553
Canadian National1636-16392886-288910/19554
Canadian National1640-16462902-29084/19567
Canadian National1647-16532909-29155/19567
Canadian National1654-16592916-29216/19566


  • Kirkland, John F. Diesel Builders, The:  Fairbanks-Morse And Lima-Hamilton. Glendale: Interurban Press, 1985.
  • Pinkepank, Jerry A. Diesel Spotter's Guide.  Milwaukee: Kalmbach Publishing Company, 1967.
  • Schafer, Mike. Vintage Diesel Locomotives. Osceola: MBI Publishing, 1998.

Southern Pacific H12-44s, #2359 and #2356, carry out switching chores in the South San Francisco during April of 1973. American-Rails.com collection.

It should be noted that another variant was manufactured as well, the H12-44TS for the Santa Fe numbered 541-543. The AT&SF requested the locomotive for use in shuttling passenger trains and equipment around its Dearborn Station terminal in Chicago.

The locomotive was somewhat longer at 54 feet, 2 inches and featured the addition of a short hood ahead of the cab, which housed a steam generator to handle passenger passenger equipment.

This short hood gave the units the a road switcher-like appearance. However, they still offered 1,200 horsepower and a B-B truck arrangement. Santa Fe regularly employed the three units in yard service until 1972 when they were sold.


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It is difficult to truly articulate just how much material can be found at this website. 

It is quite staggering and a must visit!