Abstract: A brake system in which brake means such as disc brakes are provided with emergency control means which may be a part of the overall system or may be provided by separate self contained sources of pressure which may be valved to the brake means by actuation of an emergency switch. The system provides for control of multiple groups of brake means with multiple control systems each of which are operated at a pressure less than that available from the power source. Pressure between the several groups of brakes are sensed and when a selected differential is noted the full source pressure is applied to the entire brake system. This additional source pressure applied to an undamaged bank of brake means will compensate for loss of a group of brake elements and provide approximately the same braking efficiency. Provision is made to contain pressure within one of the separate systems upon the sensing of conditions indicating a leak.