What is the normal pressure range for the Main Reservoir and the pressure under which emergency brakes apply?

The normal pressure range for the Main Reservoir in a train's pneumatic system is typically between 850-1000 kPa, which allows for proper functioning and sufficient pneumatic force to operate various systems, including brakes. The pressure under which emergency brakes are activated is generally set at a threshold lower than the normal operational range to ensure safety; in this case, it's defined as under 600 kPa. This range is critical because if the system pressure drops too low, it indicates a potential failure or critical situation that necessitates immediate braking action to ensure the safety of the train and its passengers.

Having clarity on these pressure settings helps maintenance personnel and operators assess the health of the pneumatic system and take appropriate measures if the pressures deviate from normal operating ranges. The values outlined in the correct answer align with standard practices in the industry, ensuring both operational efficiency and safety compliance.