What action should a train operator take when a signal indicates stop?

When a train operator encounters a stop signal, the appropriate action is to use the route request button. This procedure is essential because it allows the operator to communicate with the control center or signal tower to verify the situation and request guidance on how to proceed safely. By activating the route request button, the operator ensures that they are following protocol and maintaining safety on the tracks.

Using the route request button also helps to prevent potential accidents that could occur from proceeding without further instructions, as the signal indicates that stopping is mandatory. Following this communication protocol is critical for effective train operations, ensuring that all actions are coordinated and conform to railway safety standards.