What does the red hand of the duplex air gauge indicate?

The red hand of the duplex air gauge is designed to specifically indicate the pressure in the straight air pipe. This is crucial for train operators as it allows them to monitor the air pressure that directly influences the performance of the train’s braking system. Maintaining the correct pressure in the straight air pipe is essential for the proper functioning of air brakes, ensuring that they can engage and disengage effectively as needed.

Understanding this pressure helps train operators to ensure that the air brake system operates safely and efficiently, contributing to overall train safety and performance. This functionality is inherent to the design of the duplex gauge, where the differentiation between the various pressure readings facilitates immediate diagnosis and troubleshooting of air pressure issues within the train.