In the UK the pre-nationalisation railway companies standardised around systems operating on a vacuum of 21 inches of mercury (533.4 Torr), with the exception of the Great Western Railway, which used 25 inches of mercury (635 Torr).
Westinghouse Air Brake Company | vacuum cleaner | Railway air brake | Brake | Vacuum Oil Company | Brake (Unterweser) | Westinghouse Brake and Signal Company Ltd | disc brake | Vacuum fluorescent display | Otto, Count of Lippe-Brake | air brake | Watson Brake | Vax (vacuum) | Vacuum pump | Vacuum permeability | Vacuum forming | vacuum energy | Vacuum deposition | Vacuum cleaner | Tom Brake | QCD vacuum | Pfeiffer Vacuum | Parking brake | Hydraulic brake | Dive brake | counter-pressure brake | Brian Brake | Brake specific fuel consumption | Brake-by-wire | brake |