What indicates the approach of an interlocking signal?

The indication of the approach of an interlocking signal is represented by a distant signal. A distant signal provides a visual cue to train crews about the status and upcoming aspects of the next signal. It is specifically designed to prepare the engineer in advance for what to expect from subsequent signals, allowing them to adjust speed accordingly and ensure safe operations as they approach the interlocking area.

In the context of railway operations, distant signals play a crucial role in communication between the infrastructure and train crews, enhancing situational awareness and promoting safety. These signals typically display aspects that indicate whether the next signal is favorable, restricting, or requires the train crew to prepare for a stop.

While cab signals and controlled signals are also important in railway operations, they serve different functions. Cab signals transmit information directly into the locomotive, alerting the engineer to signal aspects within the cab, while controlled signals are specific signals that direct train movements at junctions and terminals. Maximum authorized speed, on the other hand, refers to the maximum speed that trains are allowed to travel on a given segment of track and does not specifically indicate the approach of a signal.