There are 3 positions the angle cock can be. 1. Open 2. Partially Open 3. Closed. When they are open the angle cock allows air to travel though the brake hose on to the next car. Both cars need to have open angle cocks adjacent to each other for the air to travel between them. When uncoupling you will need to close at the least the angle cock on the car that is still attached to your train. You can close the angle cock on the car you are uncoupling from to prevent the air from escaping from the car(s) that are attached to that cut.
When coupling to a cut of cars you will want to first open the angle cock partially on the car that is at the end of your train (White Hopper) once you successfully couple to the cars to lessen the amount of air exiting the break pipe in to the potentially empty brake pipe of the newly coupled cars, which would result in a PCS error. On the first car of the cut (Green Hopper) you will want the angle cock open so the air can flow though the rest of the train once coupled. (I diagrammed the above instructions below) Once the air equalizes you can open the angle cock on the white hopper.
[Train Here] >>>>>>>>>>>>>[Partially Open]>>>>[Open]>>[Cars coupled to]



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When moving cars the hand breaks need to be released or the cars will not move. Also air should be applied though out the train line for breaking purposes when shunting cars. However independent brakes can be used in lieu of train brakes during switching operations if deemed safe and or necessary by the train crew.
I hope this answers your questions. If not I can explain further.
David
Highball Run8 Staff Member
Instrument Rated Commercial Pilot
Train Enthusiast
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