Re: Air Brakes

One slight addition/ modification to your K triple explanation Dan: The change from the H triple to the K triple is not in the quick action end, these are the same. The K triple added "retarded release". This is the cup with a spring that is on the resevoir end of a K. It has a similar purpose as the quick application feature, but on the release end of the cycle. On a long train with H triples, the cars closest to the engine would release first and cars near the back release last. With retarded release on the k's the triple piston moves toward the resevoir end when the train line is recharged. The end of the triple piston stem that passes through the slide valve contacts the sliding spring loaded device in the cup called the retarding stem. The slide valve actually moves past the ports that would allow for release momentarily, but then recenter over the ports due to the spring forcing the retarding stem back against the stem of the triple piston that pass through the slide valve. What this achieves is a momentary delay on recharging of the cars nearest the engine so the wave of air moving back in the train can reach cars near the rear and begin to release those more nearly simultaneously with the cars near the front.
Also someone posted that automatic air was invented in the the early 1890's, it was much earlier like late 1870's. For all I know widespread adoption of automatic air might have been in the 1890's?