Valve de Coupure
La plupart des engins moteurs sont équipés d'une valve permettant d'isoler la commande du frein de ceux-ci, du reste du train. Cette valve est généralement située sous le dispositif de commande de frein, dans la cabine du véhicule.
The brake cutout valves are there to ensure that, in a train with many motorized vehicles, only one train brake control device is enabled. If there were multiple, conflicts would occur, potentially resulting in dysfunctional brakes and a disaster.
When the train brake is cut out on a vehicle, its control device is no longer functional. However, the vehicle is still able to brake, as controlled by another vehicle's train brake.
The cutout valve only affects the train brake control device, but other brake types, such as independent, can still be used freely.