The FM H-12-44 was a switcher locomotive produced by Fairbanks-Morse from May 1950 until March 1961. The units had a 1,200-horsepower (890 kW), six-cylinder opposed piston engineprime mover, and were configured in a B-B wheel arrangement mounted atop a pair of two-axle AAR Type-A switcher trucks, with all axles powered and geared for a top speed of 60 miles per hour (97 km/h).
Of the 336 H-12-44 locomotives produced, 303 were for American railroads, 30 were made between August 1951 to June 1956 by the Canadian Locomotive Company for use in Canada, and one was exported to Mexico.
H-12-44s were visually indistinguishable from the predecessor FM H-10-44 until September 1952, when the Raymond Loewy design elements were removed to reduce production costs. Cab lines were squared-off, the slanted-nose styling was discontinued, and the roof visor was eliminated. The following year, the fairing over the battery box was removed and louvers added to reduce the chance of battery explosions. Production paused from May to October 1956, after which the carbodies were shortened by some three feet and outfitted with a deeper side skirt.
Sixteen intact examples of the H-12-44 are known to survive, all of which are owned by railroad museums or historical societies.
Several examples of the H-12-44 model have been preserved around the U.S. and Canada.
Weyerhaeuser Timber Company #1 is preserved at the Northwest Railway Museum in Snoqualmie, Washington. After undergoing a full rebuild and engine overhaul, the locomotive is now run only for special events with its partner caboose, White River Logging Company number 001.
Former US Army later US Steel #1845 is currently stored at Fairless Hills, Pennsylvania, undergoing restoration. It is privately owned.
Former US Army #1847 is preserved at the Golden Gate Railroad Museum in Sunol, California. It is currently operational and has been painted in "Tiger Stripe" scheme to represent Southern Pacific #1487.
Former US Army #1854 owned by the city of Ogden, Utah. The engine is stored at the Business Depot Ogden, former Defense Depot in Utah, as of March, 2024. It is currently lettered as Defense Logistics Agency #53205.
Former US Army #1855 owned and operated (on excursion trains) by Nevada State RR Museum, Boulder City, Nevada.
Former US Army unit #1860, worked at Sunny Point Military Ocean Terminal. It later went to Beaufort & Morehead Railroad in North Carolina as #1860, based at the Morehead City State Ports. The North Carolina Transportation Museum acquired the locomotive in 2004 after disposition from the State Ports. It is now on run occasionally on excursions.