What is the acceptable pressure range for the main reservoir?

The acceptable pressure range for the main reservoir is critical for ensuring the proper functioning and safety of the train's air brake system. In this context, a pressure range of 120 to 140 psi is ideal because it is significantly within the operational limits that allow effective braking and overall system integrity. This range ensures that the system maintains enough pressure to operate efficiently without risking damage or failure due to excessive pressure.

Maintaining the pressure within this range is necessary for the proper application and release of the brakes, contributing to the safety of train operations. A range outside of these parameters could either compromise braking performance or lead to safety hazards. Hence, the specification of 120 to 140 psi is aligned with standard industry practices and is essential for the reliability of the braking system.