Before attempting to stop air hose leaks, which components must be closed?

Before attempting to stop air hose leaks, it is essential to close the angle cocks. Angle cocks are shut-off valves located on the sides of railcars that control the flow of air in the brake system. By closing the angle cocks, it effectively isolates the affected section of the hose from the rest of the air system, preventing air from escaping and allowing for a safer and more controlled environment to address the leak.

This step is crucial because if the angle cocks remain open while attempting to repair or stop the leak, pressurized air can continue to escape, making it difficult to manage the repair and potentially leading to safety hazards. Ensuring that any potential air leaks are contained enhances the safety of the crew and promotes efficient maintenance practices.

The other components mentioned, while important in the overall braking system, do not directly pertain to the immediate action necessary for addressing air hose leaks.