The cab signal apparatus on the controlling engine of each train must be tested and found to be operational within ________ before the engine or control car leaves its initial terminal.

The cab signal apparatus on the controlling engine of each train must be tested and found to be operational within ________ before the engine or control car leaves its initial terminal.

• A. 12 hours
• B. 24 hours
• C. 36 hours
• D. 48 hours

Answer: (B)

Cab signal reliability must be verified before the train leaves its starting point, and the required testing window is 24 hours. This ensures the in-cab display and related signaling logic are current and functioning, so the engineer is not relying on potentially stale or faulty indications as the train moves into protected territory. If a fault is found during the test, it must be corrected and re-tested before departure.

Cab signal reliability must be verified before the train leaves its starting point, and the required testing window is 24 hours. This ensures the in-cab display and related signaling logic are current and functioning, so the engineer is not relying on potentially stale or faulty indications as the train moves into protected territory. If a fault is found during the test, it must be corrected and re-tested before departure.