What action should be taken if a train is stopped in a block system limit?

When a train is stopped in a block system limit, it is crucial to manage visibility to ensure the safety of all operations. Turning off the headlight at the request of the crew of an approaching train is the correct action because this can prevent blinding effects that may hinder the other train's ability to see the track and surroundings clearly. Communication between crews is essential in this scenario, as it allows for necessary adjustments to maintain safety standards on the tracks.

Keeping the headlight on when requested to turn it off could pose a risk to the safety of the approaching train's crew, as it may impair their visibility. Therefore, following the request of the crew aligns with maintaining operational safety and efficiency in a block system, where precise communication and adherence to signals are critical for preventing accidents and ensuring safe train operations.