What air test is required after 4 hours and 20 minutes following an emergency braking application?

The requirement for a Class 1, Initial Terminal and Road Air Brake Test after 4 hours and 20 minutes following an emergency braking application originates from safety protocols designed to ensure the integrity and functionality of the air brake system on a train. The purpose of this test is to verify that the air brake system has been restored to full operational status after an emergency situation.

Emergency braking applications can potentially stress the components of the air brake system, which necessitates a thorough examination to ensure everything is functioning properly. This test involves checking the air brake system for leaks and confirming that the brakes are responsive, ensuring that the train can safely continue its journey. Conducting this test after the specified time frame addresses any issues that could arise post-emergency and helps to prevent accidents caused by malfunctioning brakes.

In contrast, the other choices represent different types of air tests that serve various purposes or are conducted under different circumstances. A Class 2 test is performed under different parameters, primarily when a train is in a serviceable condition without the pressure of an emergency event. A Class 3 test primarily focuses on verifying the system’s responsiveness and not necessarily after such a prolonged interval following an emergency. Lastly, indicating that no air test is required contradicts the necessity for checks