@rdunniii posted:If there is pressure held on the system and the line pressure is zero that pressure would be used to apply the brakes. That is how the failsafe works. But yes, eventually it will leak out. How long that takes depends on the seals on the individual car and a few PSI might remain for a long time. If you look at the truck cylinders (not attached to the handbrakes) and they are applied then either there is residual air pressure or there is something wrong with the brakes and that is why they are sitting there.
Got any more pics of the end frame areas?
I don’t know a ton about train brakes, but it’s sort of interesting that the emergency failsafe on railroad cars isn’t more like those in tractor-trailers. There a spring applies the brakes until enough air pressure is generated to lift the “parking brake” off of the actuating rod.
Any rapid loss of air pressure results in the spring returning and applying pressure to to the control rod, which rotates the S-cam through an actuating rod. The design of the cam allows the brakes to be held on with almost no effort by the spring.
