What must crew members have on duty to ensure they can tell correct time?

Crew members must have a watch on duty to ensure they can tell correct time. A watch is a dependable and readily accessible timekeeping device that allows crew members to remain aware of time while performing their duties. It is essential for coordinating activities, adhering to schedules, and ensuring safety in train operations.

While other timekeeping devices like chronometers, digital clocks, and smartphones could potentially provide accurate time, they may not be as practical or universally available in all situations on duty. A watch is specifically designed to be worn and easily referenced throughout the work shift, making it the most suitable choice for crew members in maintaining the necessary awareness of time. This consistency and reliability are crucial in the controlled environment of train operations, where punctuality can directly impact safety and efficiency.