What is the signal used by a train operator to call a police officer?

The signal used by a train operator to call a police officer is a long-short-long-short sequence. This particular combination is significant because it helps in distinguishing the emergency signal from regular whistle signals, allowing for immediate recognition by the police or emergency responders. The long notes indicate urgency, while the short notes provide a clear differentiation from other signals that may be in use.

In the context of rail operations, proper communication is essential for safety and quick response in emergencies. Understanding these signals helps train operators ensure they can effectively communicate with law enforcement when necessary. This specific sequence allows train operators to maintain a standardized method of alerting police while out on the tracks, ensuring that all personnel are informed and react appropriately to the situation at hand.