When is a conductor required to pass the buzzer signal to the train operator?

The correct choice highlights the specific scenario when a conductor must pass the buzzer signal to the train operator. When the train is approaching a station, the conductor needs to ensure that the operator is aware of their intention to stop, alerting them to prepare for assistance with passenger unloading or boarding. This is critical for maintaining safe and efficient operations, particularly in busy stations where careful coordination is necessary to manage passenger flow.

In this context, passing the buzzer signal serves as a communication tool between the conductor and the train operator, ensuring that both parties are synchronized in their actions as the train approaches its designated stopping point. The necessity of this communication improves the overall safety and efficiency of train operations, as it prompts the operator to be more vigilant in preparation for the train's arrival.

Other scenarios, such as the train being at a complete stop or encountering delays, do not necessitate this immediate communication in the same proactive manner. While communication remains important in all operational aspects, the urgency to pass the buzzer signal specifically exists during the approach to a station for the sake of safely managing passenger interactions.