Curious why anyone would need graduated release. Basic train handling skills and knowledge of the territory should be more than enough to compensate for a function that, in my opinion, isn't needed on anything operating on a tourist railroad. It's a neat tool and I'm sure it would be fun as an engineer to knock the brakes back a bit for a smoother stop but any good engineer can work around the equipment to accomplish that anyway.

John,

When your grade changes from 3% to 1.5%, then back to 2%, with a speed reduction from 35 to 25, and then up to 40mph, graduated brakes are really handy. Unless you have dynamics. That trumps everything!

Eric

The smoothest starts and stops I’ve experienced were with quick service and graduated release. I could not feel the instance of starting or stopping. Though much of that goes to the engineers keeping it all stretched.

Hey John,
On the Mt. Rainier Railroad, there's a 3-mile straight stretch that's stair-stepped. The usual summer excursion train set (3 or 4 cars) running at 15 mph. generally didn't have enough momentum to carry the train through the flat sections at a constant rate. Graduated release allowed the engineer to keep the train speed constant and avoid short-cycling the brakes. When we ran with a much heavier train set (like the Polar Express) the momentum was there and graduated release really didn't come into play. If the track speed were to be increased (we were working towards getting the track to Class 2) the shorter/lighter train set would have the momentum it needed.

Brian

White Pass has some really goofy grades. We primarily use blended braking with dynamics and a few retainers next to the engine/s but can run just air on the cars as well. An example I'd provide is MP 19 to MP 17. In there you go from 4% at 20 MPH, onto a fairly flat bridge with a 10 MPH speed restriction, then come off the bridge and go up a short grade of maybe 2-3% before immediately tipping back over and going down 4% again at 20 MPH. The train length is usually long enough that the cars still on the bridge aren't pushing when the engine is getting ready to tip over. That would be a cool spot for graduated release. What I wind up doing is depending on the momentum and how I'm handling the train, just let everything go and the engine doesn't stretch the train out and you keep the speed where you want. If it gets too slow, just grab a minimum and let the cars gently stretch out and then start bunching them up again with the minimum and dynamics when you start to build the momentum again.

Otherwise, if I'm running air and retainers, it's way easier... you just do a little power braking and you can pin down any speed you want and its much faster and smoother than running blended brakes, all with whatever ABD? valves we're using. I'd say the same for running at TVRM or anything else I've run on a mountain grade. My argument is that UC valves are archaic and not worth saving or messing with because they're a pain to work with mechanically and you can get your engine crews to adjust how they handle the trains with a basic functioning triple valve and possibly retainers.

I'm glad HRA is working to help with these older brake valve. However finding a single car tester for old valves is next to impossible. Pabco makes a complete bolt up AB system for $8000.
Hopefully multi service can resume unit exchange soon.

Maria

This was understood and accommodated for by HRA when working on the maintenance standard. It is hoped to soon have approval for a single car device that can be assembled in any shop, and is of proper dimension and porting to test obsolete freight brake valves (AB and older).

Passenger device(s) were not (yet) considered, since there has been no regulatory change in the requirements for maintaining and testing passenger valves; what should have been performed according to pre-December 2020 Part 232 Appendix B is the same that should now be performed post-December 2020 Part 232 Subpart H. The only element the HRA-drafted standard introduces for passenger valves is the opportunity for limited COT&S extension.



So are steam locomotives and most historic rolling stock.... Philosophical opinions may vary....

-Erich Armpriester
Strasburg Rail Road Mechanical Services

If you’re an RPCA member, I think there’s still a lend/lease program of sorts with PABCO and the SCTDs. I’ll be checking on that soon myself as we own a tester in that pool. However, I don’t remember right off if it’s usable for UC. Probably some phone calls are necessary. I’m getting back into brake work again so I’m also chasing the details as I go.

>Curious why anyone would need graduated release.

Graduated release is for reducing the resulting brake cylinder pressures made at "high speeds" when train speed is greater than about 60 mph and the train is equipped with cast iron the brake shoes. At these speeds, typical braking ratios can approach 200-250% in order to produce acceptable retardation. Then as the train slows down, and the coefficient of friction increases, it's necessary to reduce the cylinder pressures (and therefore the braking effort) to prevent slid wheels. The cut-off point, so to speak, is usually 40 mph.

>Basic train handling skills and knowledge of the territory should be more than enough to compensate for a function that, in my opinion, isn't needed on anything operating on a tourist railroad.

The problem with tourist RRs and museum operations is that the engineers/motormen tend to fan the brake too much. All too often an insufficient amount of time is allowed to recharge the auxiliary reservoirs before re-applying the brakes.

>The smoothest starts and stops I’ve experienced were with quick service and graduated release.

Quick service has nothing to do with smooth brake applications on passenger trains because it was designed for controlling slack action in freight trains longer than about 30-35 cars. Passenger trains are never this long, and in fact if you make a greater than 6 psi initial brake pipe reduction, which is typical with passenger train brake applications, QS is bypassed (on both P and F systems). The smoothness of starts and stops has everything to do with how the E performs power braking, which is a disciplinable offense on today's RRs (a policy which I do not agree with).

> However finding a single car tester for old valves is next to impossible.

There are two types of single car testers: freight and passenger; the air gauges and valve are marked as such. Even though an F tester is far more precise than a P one, per the FRA you can't use an F tester on a P system (and vice versa). The "age" of the valve being tested is irrelevant. Test racks, such as a 2-T or 3-T, are a different story, and these use a specific set of mechanical guages (which are not the air guages) for each type of triple valve. It's a similar situation with a 3-US rack because there are 4 variations of U-12 valve. AB Valves use an AB rack, and if memory serves, 22 and 26 use the 4-C rack. If you don't have a tester, you can use a locomotive's bake valve to perform the tests (provided the loco also passes tests).

Starting about 1985, WABCo make a practice of going to equipment auctions of closed RR shops and bought all the air brake test equipment, no matter the price. They did this because they wanted the repair business, and they wound up with one of the floors in the building at Wilmerding filled with test racks. I understand that all of these have were scrapped about 10-15 years ago during all the corporate shell games. Even if you have an AB or 4-C rack, you also have to have the right set of test plates, which are also hard to come by (and pricey).

Hi
Did the HRA conference get recorded to view? EBT only tests UC valves. If they fail you are done.


Thanks

MariaB,

Recordings of the sessions of the virtual HRA conferences over the past couple years can be had here: https://heritagerailalliance.wildaprico ... -Streaming.

Erich Armpriester
Strasburg Rail Road Mechanical Services

Here at the East Broad Top our procedure when customers send us their UC valves is to disassemble, clean, inspect, make minor repairs/adjustments, reassemble and then test them on one of our two USB test racks using the most recent applicable code of test.
If they are found to need any additional work which falls outside of the normal service/set price, customers are notified and given a separate quote for the additonal parts or repairs.
The same process is followed when we are servicing triple valves.
Anyone interested in receiving a quote or wanting additional information please email me.
rfreitag@eastbroadtop.com
Ron Freitag
Chief Car Inspector
East Broad Top Railroad