What must a train operator do when in doubt regarding a signal?

When a train operator is in doubt regarding a signal, the most appropriate action is to stop and seek clarification from the dispatcher. This protocol ensures safety and adherence to operational regulations. The dispatcher is responsible for overseeing train movements and has the necessary information to provide clarification about any signal that may be unclear.

Stopping in this situation prioritizes the safety of the train crew, passengers, and the integrity of the rail system. It prevents the risk of proceeding under potentially hazardous conditions, which could lead to accidents or collisions. Furthermore, taking a moment to clarify the signal ensures that the operator understands the correct course of action to take, ultimately promoting effective communication and operational safety.

Continuing with cautious observation could lead to misinterpretation of the signal, which heightens the risk of accidents. Disregarding the signal until clarification is received also poses significant safety risks, as it could mean continuing without the necessary knowledge of track conditions or upcoming obstacles. Signaling for confirmation from the next train is not a standardized or reliable method of resolving uncertainty and could lead to miscommunication. Hence, seeking direct clarification from the dispatcher is the safest and most responsible choice.