When air brakes need to be retested you must:

• A. Charge the brake pipe pressure at the rear car to within 15 PSI of the regulating valve setting (75).
• B. Be sure the brakes are released for 1 minute.
• C. Increase the brake pipe pressure to 100 PSI.
• D. Have the engineer sign off on the retest.

Answer: (A)

When checking the air brake system after maintenance, the key step is to re-charge the brake pipe and verify that the pressure at the far end of the train is close to the regulator’s setting. This ensures the entire system has been charged evenly, reveals any leaks, and confirms the brakes will release and apply properly under normal operation. Therefore, bringing the rear car’s brake pipe pressure up so it matches the regulator setting within a small tolerance is the required action. Simply releasing the brakes for a minute, pushing pressure higher than normal, or needing an engineer’s sign-off do not by themselves confirm the system is correctly charged or free of leaks.