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 (1,200 kW) 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.