These motors are located in two trucks which support the locomotive weight and distribute it to the driving wheels. The throttle electrically controls speed and power by actuating a governor mounted on the engine and by tying the response of the locomotive power control system to throttle position. The main generator converts the engine's mechanical power to electrical power, which is then distributed to the traction motors through circuits established by the various switchgear components in the electrical cabinet. At locomotive start the throttle controls electrical devices that provide rapid power response at a level consistent with smoothly controlled starting. The locomotive is equipped for performance control.
Electrical devices operating within traction motor capabilities control power at an optimum level.
This is done to achieve the desired minimum continuous speed capability at full power and the desired short time power rating. The load regulator, however, remains the main power controlling device, and through most of the operating range of the locomotive maintains power output at the specific level called for by throttle position. The air compressor maintains reservoir air pressure to be used primarily for the air brakes. The air brakes are controlled by the operator through suitable equipment in the cab. Except for manual operation of the cab controls, the locomotive operation is controlled automatically by the excitation and power control system.