What does a puff of air heard after cutting in the electric brake indicate?

When you hear a puff of air after cutting in the electric brake, it indicates that the release magnet on the head car is energized. This sound typically signifies that the braking system is transitioning from a released to an engaged state or is properly functioning following an operational command.

The energization of the release magnet allows the brakes to release, ensuring the train can move smoothly. Hearing the puff serves as an auditory confirmation that the system is responding as expected when the electric brake is activated, indicating that the brake components are functioning correctly and engaging properly with the train's control systems. In this context, it assures the operator that the air pressure is being managed appropriately in relation to the brake system.