Pull hard on red ball on trip cable to close fuel-oil shutoff valve at fuel tank. Pull overspeed trip lever at engine. When the throttle is first opened, the control circuits are energized, the generator is connected to the traction motors, and the locomotive starts to move. Successive advancement of the throttle acts on the governor to admit more fuel to the engine. The engine speed will increase until it reaches the setting of the governor as controlled by the throttle.
More power is delivered to the generator and thus to the traction motors.
When the locomotive has accelerated to the desired speed, ease back on the throttle to the point where the speed is maintained. With engine running and controller handle in an operating position, never leave the throttle open if the locomotive is not moving as this can seriously damage the traction motors. As locomotive speeds increase, traction-motor current decreases and voltage increases over a relatively wide range. Consequently, the controller has these three positions for both Forward and Reverse . The positions selected depend on operating conditions.