Which of the following scenarios would require stopping at a signal?

Stopping at a signal is an essential safety procedure in railway operations, particularly when a stop signal has been received. A stop signal indicates that the train must halt before reaching the signal. This is usually due to potential hazards ahead, such as another train on the track, track work, or any situation where proceeding could pose danger to the train or its passengers. Therefore, when a train engineer receives a stop signal, it is a direct instruction that mandates immediate action to ensure safety and compliance with regulations.

In contrast, passing through a station typically does not require a stop unless otherwise directed by specific signals. Continuing on a clear track implies that there are no current hazards, and stopping is unnecessary. Meanwhile, taking a scheduled lunch break is a planned downtime rather than an operational cue from signals. Thus, recognizing the implications of signals is crucial for train engineers in ensuring safe railway operations.