What should be done if the stop arm fails to clear?

For a situation where the stop arm fails to clear, the appropriate action is to report the incident to the engineer. This is crucial for several reasons. Firstly, the engineer is responsible for ensuring the safety of the train operations and needs to be aware of any mechanical issues that could potentially lead to accidents or unsafe conditions. The stop arm is a critical safety mechanism designed to signal to trains when to stop, and if it is not functioning correctly, it could lead to serious safety risks.

Forcing the stop arm down and securing it with a hook might seem like a quick fix, but it does not address the underlying issue and can create additional dangers. It may also violate safety protocols or company policies regarding maintenance and repair procedures. The passengers should not be directly notified in this situation as it could cause unnecessary panic or confusion, and ignoring the problem could lead to a catastrophic failure later on. Thus, notifying the engineer ensures that the problem is logged and that appropriate measures can be taken to rectify the situation safely and efficiently.