What action is taken before cutting out operating controls on a locomotive?

Applying hand brakes before cutting out operating controls on a locomotive is a critical safety measure. This action ensures that the locomotive remains stationary and under control while the operational adjustments are being made. If the operating controls were to be inadvertently engaged or malfunctioned during the process, having the hand brakes applied helps prevent any unintended movement that could lead to accidents or injuries.

Stabilizing the locomotive with the hand brakes provides a secure environment for maintenance and ensures the safety of personnel working on or around the train. This preventative measure is especially important as it reduces the risk of rolling or drifting, which can occur if brakes are not properly engaged during maintenance procedures.