Brakes

[Scruffy]

Hi everyone. Newbie here. Given the fact that braking is such a component of the operation of locomotives and their cars, understanding everything involved is huge. I have been reading about George Westinghouse and how he developed the triple valve for more effective and safety braking a train. When operating your train and temporarily stopping and parked, what is the policy to determine that your train is secured if leaving the train unattended? Is the locomotive brake lever positioned in the automatic to secure the cars? If the air compressor is shut off, does the brakes still hold on the rolling stock? Thanks

 

[bnsf971]

Set the hand brakes on a specified number of cars in the train.

 

[shay2305]

Air brakes should never be relied upon to hold an unattended train or cut of cars. The best method to secure a train is to set the required number of handbrakes. Once the handbrakes are set the engineer releases the air brakes and then you wait until everything is released to see what happens. Sometime the rule will also have the engineer apply the throttle to try to move the cars. If nothing moves you reset the air brakes and finish securing the train per the company's rules. Each railroad usually has a rule to specify a minimum number of hand brakes to be set. This may be a simple "not less than 2 brakes" or there may be a chart to calculate the required number of hand brakes depending on the number of cars and the grade where the cars are parked.
Once the engine is shut down or cut away there is no longer a way to maintain air pressure in the brake system and eventually the air will leak off and the brakes will release, each brake cylinder has a spring to return the cylinder to the released position if no air is acting on the piston. If the brake system on the car is in good shape it should hold the air in the cylinder for a fairly long time. In one instance I connected up to a car that was parked for close to 2 years and it still had air in the brake cylinder. I've also see cars bleed off their air in less than a minute.