What is the primary role of a watchman during railway operations?

The primary role of a watchman during railway operations is to prevent accidents by signaling train approaches. This responsibility is crucial for maintaining safety on and around the tracks. The watchman serves as a lookout, often stationed at crossings or other critical points, to alert both rail personnel and the public to the presence of an approaching train. By flagging trains or using signals, the watchman ensures that vehicles and pedestrians are aware of the train's movement, significantly reducing the risk of collisions and enhancing overall operational safety.

The other roles listed, such as ensuring trains are on time, operating trains, or managing train crew activities, involve different functions and responsibilities that do not primarily focus on accident prevention through signaling. Each of those activities serves important operational aspects of railroads but is distinct from the watchman's critical safety role.