What signifies a need to sound the whistle intermittently after the initial warning signal (8)?

Sounding the whistle intermittently after the initial warning signal serves a crucial safety function, particularly when approaching equipment or personnel on the track. This action is designed to alert individuals who may be in the vicinity of the track, ensuring they are aware of the train's approach. It is a practice rooted in safety regulations, emphasizing the importance of keeping all workers and equipment on or near the tracks informed about the train's movements.

This practice can help prevent accidents by providing additional warnings to those who may not be fully aware of the situation, enhancing their situational awareness. The emphasis on this response highlights the responsibility of train operators to ensure that all safety protocols are followed when approaching potentially hazardous situations.