What should the black hand of the duplex air gauge read during normal operation?

During normal operation, the black hand of the duplex air gauge typically indicates a pressure range that reflects the optimal functioning of the train's air system, particularly for the air brakes. The correct reading of 110 lbs signifies that the air brake system has adequate pressure for safe and effective operation.

Air brakes rely on compressed air to engage and release braking mechanisms, and maintaining the proper pressure is crucial for ensuring that the braking system responds promptly and effectively when needed. A reading of 110 lbs indicates that the system is properly charged, providing confidence that the air brakes can perform under standard operating conditions.

Readings lower than 110 lbs could indicate potential issues that might lead to insufficient braking power, while higher readings could suggest overpressure, which can be dangerous and may result in system component failure. Therefore, consistently monitoring the duplex air gauge and maintaining it at around 110 lbs is essential for the safety and efficiency of train operations.