Vacuum Brake - Dual Brakes

Dual Brakes

Vehicles can be fitted with dual brakes, vacuum and air, provided that there is room to fit the duplicated equipment. It is much easier to fit one kind of brake with a pipe for continuity of the other. Train crew need to take note that the wrong-fitted wagons do not contribute to the braking effort and make allowances on down grades to suit. Many of the earlier classes of diesel locomotive used on British Railways were fitted with dual systems to enable full usage of BR's rolling stock inherited from the private companies which had different systems depending on which company the stock originated from.

Air brakes need a tap to seal the hose at the ends of the train. If these taps are incorrectly closed, a loss of brake force may occur, leading to a dangerous runaway. With vacuum brakes, the end of the hose can be plugged into a stopper which seals the hose by suction. It is much harder to block the hose pipe compared to air brakes.