Vehicles can be fitted with dual brakes, vacuum and air, provided that there is room to fit the duplicated equipment. In a dual fitted vehicle, there would be both a vacuum cylinder and one or more air brake cylinders, all operating on the same set of rigging to apply the brakes at the vehicle wheels. Some of BR's Mk1 coaches were built with dual brakes (all had vacuum as standard) and much of the rest of the fleet was dual fitted by the 1980s, so they could be worked by air or vacuum fitted locomotives as the changeover from vacuum to air took place between 1970 and the early 1990s.