The SD50F was a Canadian cowl unit version equipped with a "Draper taper" (inset section aft of cab for limited rear visibility). 60 were built for the Canadian National Railway as road numbers 5400-5459.  Early engine problems resulted in a temporary down-rating to 3,300 horsepower (2,500 kW).  Eventually the units were re-rated to 3,500 horsepower (2,600 kW); however, like their U.S. cousins, they continued to suffer from relatively low reliability, frequently suffering engine, power assembly, and crankshaft failures.
Out of the 60, only six of these locomotives are known to exist today, with the rest of the fleet scrapped