What could be an indicator of an air brake system leak?

A loss of brake pressure over time is a clear indicator of an air brake system leak because the air brake system relies on maintaining a specific air pressure to function correctly. When there is a leak, the pressure decreases, which can reduce the effectiveness of the brakes. This gradual loss of pressure can lead to a situation where the brakes are less responsive or may even fail, posing a significant safety risk.

In contrast, increased fuel consumption, unusual noises during operation, and worn-out brake pads may indicate other mechanical issues but do not directly point to the integrity of the air brake system itself. These other factors might affect the overall performance of the train or vehicle, but they do not specifically indicate a leak in the air brake system. Maintaining proper air pressure is crucial for the safe and effective operation of air brakes; therefore, any substantial loss in pressure should prompt immediate investigation and repair.