Monitoring

The compressed air brake system can be monitored via brake gauges, typically located in the cab of a motorized vehicle .

Reading of the main reservoir should always be near 8 bar, as 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 it is fully released. Brake pipe pressure is usually represented by a black or white needle on the brake pipe gauge.

Brake cylinder pressure goes between 0 and 3.75 bar and represents the actual braking force applied to the wheels . Brake cylinder pressure is usually represented by a red needle on the brake pipe gauge.

Since gauges display pressures relative to the atmospheric pressure, the actual absolute pressures are approximately 1 bar higher than what's indicated on the gauge and used in technical documentation.

To help improve visibility of brake cylinder reading, there is a gadget called Brake Cylinder LED Bar, which can be bought in one of the {pll|Shops|shops}}.