What should be done if a train encounters an interlocking signal that has been removed from service?

When a train encounters an interlocking signal that has been removed from service, the appropriate action is to refer to Form D line 7 for guidelines. This line provides specific instructions for handling situations where signals are out of service, ensuring that train crews know the proper protocols to follow, which may include speed restrictions, observation of other signals, or procedures for safely proceeding through the area.

Understanding these established guidelines is crucial for maintaining safety and effectively managing potential risks associated with operating in areas where signals are not functioning as intended. Relying on Form D ensures that the train crew adheres to the company's operating rules and maintains communication with track authorities for any additional instructions.