Under what condition can a train operate on the indication of a Clear signal?

A train can operate on the indication of a Clear signal when the leading end passes the Clear signal because this indicates that the track ahead is clear for the train to proceed safely. The Clear signal is an important aspect of railroad operations, signifying that there are no obstructions or restrictions on the track further along.

Understanding this condition is critical for ensuring the safety and efficiency of train movements. The train crew must acknowledge the signal displayed at the leading end, as this is the point where they confirm they have the authority to proceed. This practice minimizes the risk of accidents and ensures that all safety protocols are followed.

In contrast, relying solely on consent from crew members, the dispatcher’s go-ahead, or the train's entry into a block could lead to misunderstandings or unsafe conditions, as these factors do not guarantee that the track is clear and safe for movement. Thus, the correct procedure is to proceed only after the leading end has passed the Clear signal.