Monitoring

The brake system can be monitored via brake gauges, typically located in the cab of a motorized vehicle. The main reservoir reading should always be high, up to 8 bar and it is automatically refilled by the compressor. Brake pipe operating pressures are between 3.5 bar when the brake is fully applied and 5 bar when fully released (since gauges display pressures relative to the atmospheric pressure, the actual absolute pressures are approximately 1 bar higher than indicated on the gauge). Brake cylinder pressure goes between 0 and 3.75 bar and represents the actual braking force applied to the wheels. As brake gauges are sometimes shared by multiple needles, the brake cylinder pressure is normally represented by a red needle on the brake pipe gauge.

See also: Air Brake System Overview, Cylinder Leaks, Manual Cylinder Release, Train Brake, Independent Brake, Brake Shoes