How does a parking brake function in air brake systems?

A parking brake in air brake systems is designed to hold the vehicle stationary when engaged, which is typically achieved through the use of spring brakes. When the air pressure is released, springs within the brake mechanism are activated, pushing the brake shoes against the drum or disc. This ensures that the vehicle remains in place, especially on inclines or during periods of inactivity.

The effectiveness of the parking brake is critical for safety, as it prevents the vehicle from rolling unintentionally. Understanding this function is essential for proper vehicle operation and maintenance in air brake systems.