J.B.Bane Wrote:
-------------------------------------------------------
> 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 quick action 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. P1's mount
> with 3 bolts as I recall like a K2 or H2. 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.
A very small nit to pick: The difference between an "H" and a "K" is the K valve has a "retarded release and recharge" feature. That is what that big end cap on the reservoir end the valve does.
Under that cap is the retarded release spring. The idea was that the cars on the rear end of a long (more than 50 cars) train did not charge as fast as the cars on the head end, resulting in the cars up front doing all the work. The retarded recharge feature slowed the release and recharge of the front end cars while allowing the cars on rear to recharge and do their part. When the brakes are released a large wave of air is sent down the brake pipe. This wave decreases as it moves toward the rear. At the back end it becomes a slow rise in pressure. The cars up front that see the big wave of air, have enough pressure against the triple piston to compress the spring and move the slide valve into retarded release and recharge, while the cars on the rear see the gentle rise and the piston does not compress the spring.
The size trains we all run will see the entire train releasing in retarded release. I saw this in the 20+ car trains we used to run. If you are next to the retainer vavle when the brakes release you can hear the valve go through retarded release. Initially there will be a blast of air out the retainer as the triple moves to release. Then, the air out of the retainer will slow as the valve is pushed into retarded release. It will continue to release air this way until the cylinder air almost completely exhausted, then the valve will move back it full release. The last bit of air in the cylinder them comes out of the retainer in a final sigh...
