From 1944, Fairbanks-Morse offered the H-10-44 as a yard switcher with a two-stroke, six-cylinder, opposed-piston engine. The exterior was designed by Raymond Loewy, which could be recognized by a slanted nose, sloping shapes and a protruding cab roof. After many had been later set to 1,200 hp, the H-12-44 with the same power was offered from 1950. From 1952 the exterior was simplified to save on production costs. The H-12-44TS was a road switcher with a short hood in front of the cab. This variant was only built three times for the ATSF. 