Union Pacific Air Brakes Practice Test

The requirement for an air brake test on the rear car of the train is fulfilled by demonstrating a decrease in pressure of 5 PSI and an increase of 5 PSI. This procedure helps to ensure that the air brake system is functioning correctly. The decrease indicates that air is being released from the system when the brakes are applied, while the subsequent increase shows that the system is capable of re-pumping the air, which is vital for confirming that the braking system can effectively operate when needed. When performing air brake tests, the pressure changes observed are critical indicators of the brake system's health and responsiveness. Monitoring these pressure changes helps to verify that there are no leaks or malfunctions within the brake system, ensuring the safety and reliability of the train's operations. Therefore, the measurement of both a decrease and an increase in pressure is a fundamental part of assessing the overall functionality of the air brakes on the rear car.