What is the maximum allowable brake pipe leakage per minute during the test?

The maximum allowable brake pipe leakage per minute during the test is 5 psi. This standard is established to ensure the integrity and efficiency of the air brake system. A leakage rate of 5 psi indicates that the system is maintaining relatively tight seals and pressure, which is crucial for safe train operations. If the leakage were higher than this threshold, it could compromise the air braking capacity, leading to potential safety hazards.

Lower leakage rates, such as 1 or 2 psi, while potentially indicating a well-functioning system, are not the maximum standard set for tests. This means they do not represent the threshold that can still be deemed acceptable while still allowing for some degree of system wear over time. A threshold of 10 psi would suggest a significant issue with the brake system, indicating the need for maintenance or repairs to ensure safe train handling and operation. Thus, 5 psi serves as a balanced maximum that aligns with acceptable operational standards while ensuring safety.