I can't immediately address the difference to an L triple, but as Brian said above a k1 and k2 are functionally the same in principal of operation. A K2 is designed with bigger ports to correspond with supplying air to bigger brake cylinders that would be found on std. ga. freight cars. I have seen K1's on several std. ga. cabooses with 8" brake cylinders, but in general I think K1's are going to be found on NG equipment with 6 and 8 inch brake cylinders and k2's for 10" brake cylinders common to std. ga. cars. They are not readily interchanged thanks to the k1 mounting with 2 bolts and the k2 with 3. H triples can be thought of as the interchangeable predecessor to the K triple so the H1 and H2 interchange with K1 and K2 respectively. The H has a narrower slide valve and lacks the retarded relaease feature added to the K. They were often sent to WABCO and factory converted to the functionality of a K. A K or converted H has a wing on the top to distinguish them apart from an unconverted H at a glance. The converted Hs have the wing attached with a screw, while the wing is part of the K casting. Another very similar variant is the P triple.. Correct me on this someone if I am wrong. We have one car at SVRR with an H1 that I rebuilt years back which is on our "Leviathan" which is a small std. ga. business car running on NG trucks. It has a 10" brake cylinder. The slide valve is narrower than a K1 triple and probably the same as an H1, but with noticeably bigger ports. I had a machine shop make me a lapping tool for the K1 and H1's. One way it is the right width for the K1 seat and turned 90deg. the other way narrower for the H1's. As I recall the narrow side worked correctly on the P1 I dealt with. I had good success with between 15 and 20 triple valve rebuilds at SVRR years back some of which were made up of parts from several to make one. The 2 or 3 failures I had were all due to lack of patience in lapping. This can not be stressed too much.
Edited 2 time(s). Last edit at 02/21/2017 10:53AM by J.B.Bane.
