THREE CANADIAN PACIFIC RAILROAD CREW DIED WHEN THE AIR BLED OFF OF THE BRAKE ACTUATING AUXILIARY COMPRESSED AIR RESERVOIRS. THEIR FREIGHT TRAIN ROLLED AWAY DOWN A STEEP GRADE AND CRASHED DOWN A BANK AT A CORNER NEAR A BRIDGE.
THE WESTINGHOUSE AIR BRAKE SYSTEM HAS A RESERVOIR OF COMPRESSED AIR WHICH WHEN THE BRAKE PIPE LINE PRESSURE IS REDUCED ACTIVATES A MECHANISM THAT APPLIES THE TRAIN'S BRAKES.

The Engineman, the Driver of the Train " Stepped off" his unit and did not secure a hamdbrake or other brakes.The handbrake is a mechanical device, air brakes are releaseable remotely or by bleeding off. Handbrakes and wheelchoks were my rule. In 1969 air brakes bled off an empty passenger train, it rolled out of the railroad station at Main and Terminal in Vancouver BC headed towards the main line. The story of how I and my crew split my Royal Mail train and caught the passenger train with my freight train is another story.