What PSI is achieved when the retaining valve is in the High Pressure position?

When the retaining valve is set to the High Pressure position, the system is designed to achieve 20 PSI. This setting is critical for maintaining proper brake function, especially in situations requiring additional braking power. The High Pressure position allows for a stronger application of brakes, which is particularly useful in scenarios such as descending grades or when the train is under heavy load. By ensuring that 20 PSI is reached, the retaining valve reduces the chances of brake release under dynamic conditions, providing better control and safety in train operations. Understanding the correct pressure settings is crucial for effective air brake management and contributes to the overall safety of the train's operation.