Re: Air Brakes

Dan, I should have known I was on shaky ground discussing air brakes with you. I believe I misspoke. Retarded release/uniform recharge is a feature of K triples not present on the H, however after thinking about it, I got my terms mixed up with regard to "quick action" and "quick service". Both H and K have "quick action" which if memory serves me from past reading refers to how the valve acts in emergency. "Quick service" as you say is an innovation in the K. Tell me if this sounds right: In an initial service application which I believe the old Westinghouse books say is a5-6lb reduction, this being what it takes to overcome friction in the triple valve and enough to cause the triple piston stem to strike the graduating stem and compress the graduating spring. Like with retarded release, the triple piston and slide valve only remains in this position momentarily as the spring forces the graduating stem to push the triple piston and slide valve back to the normal application position. During the moment the graduating spring is compressed the slide valve is lined up over ports such that a small amount of train line pressure is diverted to the brake cylinder causing a localized dip in the trainline pressure which in turn causes an acceleration in the response of the next triple valve back in the train. This process being sequential, but more nearly simultaneous than would occur without the quick service feature. I'll probably go home tonight and read up on this to see if I just made a fool of myself!
I have rebuilt quite a few K1's and a few H1's, so am quite familiar with the internal parts. At least a couple times with an ICS book in front of me and a valve dismantled I have gone through the functions of each part, but it is kind of a use it or loose it thing as far as what I learned.