What whistle signal must be sounded when approaching roadway workers?

The correct answer is that two short signals must be sounded when approaching roadway workers. This practice is in place to ensure the safety of personnel working near the tracks. The two short signals serve as a warning to alert roadway workers of the approaching train, allowing them to take necessary precautions and clear the area if needed. This signaling procedure is crucial for minimizing the risk of accidents and ensuring that both the train crew and the workers maintain a high level of awareness regarding each other's presence.

Understanding the importance of signaling is vital in railroad operations, as it facilitates communication and enhances safety protocols in situations where personnel may be close to moving trains.