Locomotive Engineer Trainee Practice Test

The component that provides power to the traction motors is the diesel engine or electric power system. In a diesel-electric locomotive, the diesel engine generates mechanical power that is converted into electrical power by generators. This electrical power is then used to drive the traction motors, which in turn provide the necessary force to move the locomotive and any attached cars.

In electric locomotives, the power comes directly from an external source, such as overhead wires or a third rail, and is supplied to traction motors. In both cases, this connection between the power source and the traction motors is essential for the operation of the locomotive, enabling it to convert energy into locomotive movement effectively.

While options like the air compressor, wheel assembly, and fuel tank play important roles in the overall functioning of the locomotive, they do not provide the power necessary to drive the traction motors. The air compressor is used for pneumatic systems, the wheel assembly supports and helps in motion but does not generate power, and the fuel tank stores the fuel needed for the engine but does not directly supply power to the traction system.