The vacuum brake is a braking system employed on trains and introduced in the mid-1860s. A variant, the automatic vacuum brake system, became almost universal in British train equipment and in countries influenced by British practice. Vacuum brakes also enjoyed a brief period of adoption in the United States, primarily on narrow-gauge railroads. Their limitations caused them to be progressively superseded by compressed air systems starting in the United Kingdom from the 1970s onward. The vacuum brake system is now obsolete; it is not in large-scale usage anywhere in the world, other than in South Africa, largely supplanted by air brakes.
Driver's brake control in a Black 5
Graduable brake valve (right) and the small (upper) and large ejector cocks from a GWR locomotive
Driver's brake control on a combined control and ejector. The ejector steam nozzles, large and small, are beneath the hexagonal brass plugs on the left.
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction.
Disc brake on a motorcycle
Rendering of a drum brake
Single pivot side-pull bicycle caliper brake
Brake booster from a Geo Storm.