In common with other F-M locomotives, the Train Master units employed an opposed piston prime mover.

Other drawbacks were the difficulties inherent in maintaining the opposed-piston engine, inadequacies in the electrical system, and a higher-than-normal consumption of cooling water.

All these contributed to poor marketplace acceptance of the Train Masters—and ultimately the departure of F-M and CLC from the locomotive business.

Phase 1a units had air intake louvers in a continuous line along the top of the long hood and a wide separating strip between the radiator fans.

Phase 2 units had fewer air intake louvers, with large gaps separating them, and the radiators themselves were divided by a tiny metal strip.