Kazantsev Brake

an automatic single-wire direct brake for railroad rolling stock with an air distributor designed by F. P. Kazantsev.

An AP series air distributor charges the reserve tank with compressed air and fills the brake cylinder and releases the air from it. The Kazantsev brake provides stepped braking and release. Prolonged braking on long downgrades does not deplete the brake—that is, if emergency braking occurs at any instant during motion, rated brake shoe pressure is produced. However, normal braking action is possible only at a certain level of charging of the brake system, to a pressure of 0.5 meganewtons per sq m (MN/m²), or 5 kilograms-force per sq cm (kgf/cm2). Such an air distributor was called rigid, since at higher pressures no braking occurs and at lower pressures self-braking occurs independent of the rate of pressure change, thus presenting difficulties in operation. Kazantsev also designed a semirigid air distributor (series K), which made possible normal brake operation with varying pressure in the feeder. Diaphragm sealing of pistons and the use of valves in the air distributor were design features peculiar to the Kazantsev brake.

The Kazantsev brake was first used in the USSR in 1925, replacing the Westinghouse brake in freight trains. In 1933 the Kazantsev brake was superseded by a brake with an air distributor designed by Matrosov (the Matrosov brake).