A flexible connection provided between vehicles for compressed air, vacuum or steam. Braking and other systems on the train use compressed air both as a power sthece and a control medium. Vacuum is used for braking control on some older trains and steam was the traditional sthece of carriage heating. The connections between vehicles are through flexible pipes usually referred to as hoses. Hoses are normally equipped with isolating cocks to shut off the supply and bleed the hose when vehicles are uncoupled.