Which of the following is necessary for a train to operate safely when the previous signal indicates it must stop?

When a train encounters a signal that requires it to stop, the safe operation of the train is contingent upon receiving proper clearance from the dispatcher before proceeding. This ensures that the train is not only complying with the signaling system but also that a safe path has been established for its movement.

The dispatcher plays a crucial role in coordinating train movements and ensuring that all conditions are safe for trains to proceed, particularly when the previous signal indicated a stop. Without the dispatcher’s authorization, there could be unresolved issues such as the presence of an obstruction, or another train may still be occupying the track ahead. This step is fundamentally about maintaining safety and preventing potential accidents on the railway.

The necessity for clearance from the dispatcher reflects the principles of communication and authority in railroad operations, emphasizing the importance of following established protocols. This aligns with the established practices to ensure that the train is cleared for safe operation beyond a stop signal.