Regulagem

Dependendo do veículo motorizado, existem duas formas de controlar a pressão do tubo de freio: auto-regulada e a mais antiga, não-auto-regulada.

Nos sistemas de auto-regulagem, a pressão do tubo de freio é controlada automaticamente. O maquinista pode colocar a alavanca do freio do trem em qualquer posição. Quanto mais longe estiver na direção "aplicar", mais forte será a força de frenagem, e vice-versa. A válvula lida automaticamente com o descarregamento ou pressurização do tubo de freio, dependendo da posição da alavanca.

On non-self-lapping systems, the process is more hands-on. The lever has a few fixed positions. Two of the positions, called “release” and “service” can be thought of as adding and releasing the brake pipe pressure, respectively. The position in between them, called “lap”, is used to maintain whatever pressure is in the brake pipe. The furthest position, called “emergency”, will release pressure at the fastest possible rate.

Auxiliary reservoirs are being drained when braking. When the brakes are released, it takes some time for auxiliary reservoirs to fill up again. The lap position, however, functions only if the auxiliary reservoirs are full. To stay in full control over braking it is recommended to not release non-self-lapping brakes when knowing that moments later braking may be needed again. Calculated, slow moves are preferable when releasing the non-self-lapping brakes.

With both brake types, the driver can see exactly how much braking force they are applying by looking at the brake pipe and brake cylinder gauge needles.

Ambos os sistemas são bastante simples de usar, embora a auto-regulagem possa ser mais intuitiva para iniciantes. Em termos simples, com auto-regulagem, o dispositivo de controle define a força de frenagem desejada, deixando para a válvula automática fazer o trabalho, enquanto com não-auto-regulagem, o dispositivo de controle define diretamente a força de frenagem.

In case a train contains motorized vehicles with both self-lapping and non-self-lapping brake valve types, only the self-lapping ones will be functional when operating the brake. For that purpose, vehicles are also equipped with brake cutout valves, which can be used to isolate certain vehicles from the brake system and resolve this conflict.