What action should be taken if there is no door light on the train?

If there is no door light on the train, the appropriate action to take is to walk the train and look for open doors. This is important for ensuring safety and security on the train. The door light serves as an indicator that the doors are properly closed and secured. If the light is not functioning, it could suggest that a door is ajar or not sealed correctly, potentially leading to safety risks for both passengers and crew.

By physically walking the train and checking each door, the crew can confirm the status of all doors and take necessary actions to close or secure any that may be open. This proactive measure is critical for maintaining operational safety and preventing accidental departures with doors unsecured.

Other options, such as checking water levels or inspecting train wheels, do not directly address the issue of the door light and are not relevant to ensuring the immediate safety and readiness of the train for passenger operation. Inspecting the overhead lights may also not provide any useful information regarding the door light's status, as it does not resolve the specific concern about door security.