automatic hand brake release ppt

ABSTRACT
A system is presented for automatically releasing all handbrakes of a railroad freight car or passenger car system. Working from the main air brake pressure lines, a pressure switch is provided which trips once the air pressure for the separate air brake system of a freight train or passenger train is reached. This pressure switch in turn energizes another mechanism, either a piston or other internal types of mechanical connection, which then pushes up the brake lever release releasing the handbrake. Since each handbrake on each end of each car is connected to the main air brake system through pressure sensitive valves, all manual handbrakes are released on all cars once the air pressure of the train is brought up to a certain level.