Bendix air brake has made a school available to anyone interested. It appears to have alot of very good information. You will have to setup an account to use. Brake-School.com (http://www.brake-school.com/public/)
Which is a good lead in for anyone attending Q soon. I have 12 copies of the complete course material for taking your Commercial Truck Drivers exam here in Canada. Yes I know it will not do for US but this 300 page book explains all about Air Systems and Brakes etc etc etc including all the valves and what they do on a truck and trailer system. It has built in Questions to test yourself and is required reading/and passing to get either a class 1,2 or Brake Endorsement ( if vehilcle has air brakes rather than Hydraulic).
I will be giving them away once we get there and I am sure anyone that gets one from me will have interesting reading for a few weeks. It is a good reference book when you are not sure what is causing a problem in your system.
JohnH