Autostop, used in the automatic blocking of the metro, is a set of travel and train devices. The train devices include the pneumatic snapping valve and the universal auto-stop switch UAVA.

A tear-off pneumatic valve is attached to the brake line pipe. When the valve is open, the brake line is discharged into the atmosphere through an opening in the valve body. When the valve is closed, the atmospheric opening and the brake line are separated – the air outlet to the atmosphere is closed.
The working body of the pull-off valve, which interacts with the track part, is a clamp, which is fixed in a vertical position by two retracting coil springs. Turning the caliper when striking the working body of the track unit results in the opening of the valve and emergency braking of the train.

The universal auto-stop switch UAVA is connected to the brake line in front of the pneumatic pull-off valve. In case of emergency braking of a train from auto-stop, UAVA is activated and disconnects the traction motors, if they worked ^ in traction mode. With the help of the UAVA, the locomotive crew disconnects the train hitchhiking (closes the brake line in front of the valve) in the case of a prohibitory signal following the order established by the PTE of the subways. The tear-off pneumatic valves located in intermediate train cars (between the head and tail cars) are also normally shut off by means of AVAB.

For reliable interaction of the train hitch with the track part, the height of the suspension bracket of a sryvny valve above the level of rail heads is 53-55 mm.The working body of traveling hitchhiking (Fig. 6.8) is a shock lever, installed on the right side of the track in the direction of train travel. The impact lever can occupy two positions: horizontal, not interfering with the movement of the train, and vertical, interfering with its movement. When autostop is closed, the impact arm rises above the level of the head of the running rail within 85–90 mm.