Supervisión
El sistema de frenos de aire comprimido se puede supervisar a través de indicadores de freno, generalmente ubicados en la cabina de un vehículo motorizado.
La presión de la reserva principal siempre debe ser de (o cercana a) 8 bares, y se rellena automáticamente mediante el compresor.
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, and its pressure is controlled by the train brake control device.
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.