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Old 07-10-2013, 11:14 PM
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dalray dalray is offline
 
Join Date: Sep 2012
Location: Edmonton Alberta
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Quote:
Originally Posted by Kokanee9 View Post
Each railcar has its own brake system to apply and release the bakes on that particular car. The cars themselves do not have an air compressor. The supply of air to charge the system comes from the locomotives. I think the "header" you referred to, are the rubber air hoses that you see on both ends of each car. That is common link between each car that lets the air pressure be controlled from the engines.
Think of it as a solid air pipe (trainline) from the engines to the very last car on the train. Each car will have another pipe branching off of this main one (the trainline) to control the air brakes on that particular car. The leaking from one of the reservoirs that I referred to, actually leaks into the trainline, not out to the atmosphere. (remember the brakes need pressure to release) When the pressure in the trainline has increased by 1.5 psi, a control valve on the car next to the leaking one is activated and it in turn will start putting air into the trainline. The next car senses the 1.5psi increase and it then starts putting air from a resoirvoir into the trainline. This is how the chain reaction is started. The control valve on each car is operated pneumatically and only knows what is happening at that particular car. It doesn't know if the train is moving or stopped, unattended or manned. It just senses a rise or fall in the trainline air pressure at that car.
The system is actually designed this way to make the brakes release faster when the train is being operated.



Not pumps, the air leaks from a resorvoir on one of the cars into the trainline. As the equipment gets older, it is not as air tight as it used to be. There are no pumps or compressors on the rail cars themselves.



I don't have an automotive class 1 air brake license, but if I understand it right, those brakes work in reverse of how trains work. Air pressure is increased to apply the brakes. Originally trains worked this way until the early 1900's when a better system was designed. The problem was if the train broke apart, there was no way to apply the brakes any more. That wasn't good.



Hope I explained it better.
You are 100% correct, the secondary valve is called an aav valve. Located on the service portion.
Which Railroad do you work for and dept.
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