FM H-16-44, Class FS16m

The FM H-16-44 was a road-switcher produced by Fairbanks-Morse from April 1950 – February 1963. The locomotive shared an identical platform and carbody with the predecessor Model FM H-15-44 (but not the FM H-20-44 end cab road switcher which used a different carbody and frame and a larger prime mover), and were equipped with the same eight-cylinder opposed piston engine that had been uprated to 1,600 horsepower. The H-16-44 was configured in a B-B wheel arrangement, mounted atop a pair of two-axle AAR Type-B road trucks with all axles powered. In late 1950, the AAR trucks were almost exclusively replaced with the same units found on the company's "C-liner" locomotives.

As with many of their F–M contemporaries, the H-16-44s produced through 1954 featured numerous Raymond Loewy design touches, in this case largely manifested in the form of sloping body lines and a noticeable protrusion in the long hood around the radiator shutters. Cab side window units include inoperable "half moon"-shaped panes, resulting in an oblong-shaped assembly. To reduce manufacturing costs, the curved window panes were eliminated from later models, and from 1953 onward the raised, elongated headlight mounting was omitted. Units built in the "Spartanized" fashion can be spotted by their straight ends, coupled with the lack of superfluous trim. Ventilation slots were added at the battery box to reduce the possibility of explosions. The final production phase, which commenced in March 1955, turned out units that most closely resembled the Fairbanks–Morse "Train Master" series.

209 were built for American railroads, 58 were manufactured from March 1955 – June 1957 by the Canadian Locomotive Company for use in Canada, and 32 units were exported to Mexico. 

FM H-20-44, Class FS20 / FS20m

The FM H-20-44 was a multiple unit-capable end cab road switcher manufactured by Fairbanks-Morse from June 1947 – March 1954, and represented the company's first foray into the road switcher market. The 2,000 hp, ten-cylinder opposed piston engine locomotive was referred to by F-M's engineering department as the "Heavy Duty" unit. It was configured in a B-B wheel arrangement mounted atop a pair of two-axle AAR Type-B road trucks with all axles powered. H-20-44s shared the same platform and much of the same carbody as the lighter-duty FM H-15-44, which began its production run three months later.

In the same manner as other F-M switcher models, the H-20-44 started out displaying a variety of Raymond Loewy-inspired contours, only to have the majority of these superfluous trim features stripped from the last few units built as a cost-cutting measure. Only 96 units were built for American railroads, as few firms saw sufficient value in moving freight in greater quantities or at a higher speeds than was possible with the typical 1,500- and 1,600 horsepower four-axle road switchers of the era. Also limiting the model's utility as a true road unit was its lack of a short hood, which the (ironically) lighter-duty H-15-44 did have. 

FM H-24-66 "Trainmaster", Class FS24m

The H-24-66, or Train Master, was a diesel-electric railroad locomotive produced by Fairbanks-Morse and its licensee, Canadian Locomotive Company. These six-axle hood unit road switchers were deployed in the United States and Canada during the 1950s.

They were the successor to the ultimately unsuccessful Consolidated line of cab units produced by F-M and CLC in the 1950s. Each locomotive produced 2,400 horsepower. In common with other F-M locomotives, the Train Master units employed an opposed piston prime mover. The model rode on a pair of drop equalized three-axle "Trimount" trucks giving it a C-C wheel arrangement.

Touted by Fairbanks-Morse as "...the most useful locomotive ever built..." upon its introduction in 1953, the 2,400 horsepower H-24-66 Train Master was the most powerful single-engine diesel locomotive available at the time, legendary for its pulling power and rapid acceleration. No competitor offered a locomotive with an equal horsepower rating until ALCO RSD-7 entered production in January 1954 (EMD followed suit later in July 1958 with SD24, and GE introduced their U25C in September 1963).

While some railroads saw advantages in the Train Master's greater power, the perception on the part of others that the unit had too much horsepower (coupled with the difficulties inherent in maintaining the opposed-piston engine, inadequacies in the electrical system, and a higher-than-normal consumption of cooling water) contributed to poor marketplace acceptance of the Train Masters. Both F-M and CLC ultimately left the locomotive business.

Three different carbody variants were produced, and were differentiated as follows: Phase 1a units had their air intake louvers located in a continuous line along the top of the long hood, and a wide separating strip between the radiator fans; Phase 1b modifications were minor, consisting only of a "dip" in the long hood handrails that allowed them to better follow the profile of the side walkways; Phase 2 units boasted fewer air intake louvers, with large gaps separating them (the radiators themselves were divided by only a tiny metal strip).