- a stopcock of the brake line, used to close it at the ends of the train, in the middle or in any part of it (when uncoupling). The end cock is installed at both ends of each car and locomotive. A distinctive feature of the end cock is that when closed, it releases the fluid from the flexible inter-car hose of the line through special side holes; this facilitates the separation of the hoses in the inter-car space of the train when it is uncoupled.