What is the purpose of performing a brake test on an air brake system?

The primary purpose of performing a brake test on an air brake system is to confirm that the system is functioning correctly before a trip. This is crucial for ensuring the safety and reliability of the train during operation. The brake test verifies that the brakes are responsive and can slow or stop the train effectively, which is fundamental to prevention of accidents and ensuring the safety of both the crew and the cargo.

While checking for signs of wear on brake pads, assessing fuel efficiency, and evaluating speed limits are important aspects of train maintenance and operational safety, they are not the primary focus of a brake test. The brake test specifically targets the operation of the air brake system to ensure it is in optimal working condition, highlighting the critical nature of this procedure in train operations.