vacuum brake

Noun

vacuum brake (plural vacuum brakes)

1. A brake used on trains, working on the principle of keeping up a vacuum in a continuous pipe or pipes extending under the train, and in brake-cylinders connected to them under each vehicle, the air being sucked out by ejectors or pumps on the locomotive.
   • Compressed air is used for the operation of certain contactors, the sanders, the horn, and the re-fuelling equipment, but vacuum brakes are fitted to the locomotive.1951 January, “Diesel-Electric Branch-Line Locomotive for British Railways”, in Railway Magazine, page 71
   • Consideration of recent pronouncements and predictions shows second thoughts to be practicable, in particular, on the technical decision for which the previous B.T.C. regime was most hotly criticised by experts - the adoption of the vacuum brake as standard for the modernised British Railways....1963 January, “A second chance on brakes”, in Modern Railways, page 1