What action must a crew take if a semaphore arm is visible during an improperly displayed signal situation?

The appropriate action for a crew when encountering a semaphore arm during an improperly displayed signal situation is to regard the semaphore arm's position as governing. This means that the crew should interpret the signal as it is displayed, which provides critical information regarding the train's movement and safety on the track.

Semaphore signals are designed to communicate specific instructions to train crews. If the signal is improperly displayed but the semaphore arm is visible, the established protocols dictate that the crew treat it as the authoritative directive until they receive further information. This protocol is in place to ensure safety and adherence to established rules, eliminating any ambiguity when signals might be malfunctioning or displayed incorrectly.

In this scenario, ignoring the semaphore arm or assuming it indicates a stop could lead to safety risks or delays due to miscommunication. Consulting the dispatcher might be necessary in cases of uncertainty or unusual situations, but when a semaphore arm is visible, it serves as the operational signal that should be followed. Thus, taking the position of the semaphore arm into account is crucial for safe train operations.