I am looking to find a piping schematic and operation/maintenance manual for the P type triple valve braking system. I am working on Lackawanna Boonton coaches that still have the system in place. The triple valves are being serviced at an air brake shop. I was just looking for an O&M manual on how all of the components work together. (Specifically the High Speed Reducing Valve mounted off of the cylinder)

The funny thing is that the only information about it that I have come up with so far is from the 1926 Car Builders Encyclopedia. It stated that the P type system was already obsolete on new construction by then! I've talked to Westinghouse and they could not find anything in the archives on the Ps. If anyone had a manual, it sure would help me out to obtain a copy if possible.

Thanks,
Pat Connors
BSOR CMO

Pat:

Eighteen of our coaches have the PM system. The branch pipe is fairly straightforward, running through a cut-out cock and then through a centrifugal dirt collector. We use the kind of dirt collector that is tapped on the bottom so that it can be blown out weekly. After the dirt collector, the branch pipe ties in directly to the bottom of the valve with a rubber-seated WABCO union, the valve body serving as the male portion of the union.

The auxilary res ties in to the mounting plate for the valve, at either 9 or 3 o'clock. If you are unsure about the proper volume of your AUX res., call me Monday at 717-687-8421 and I'll let you know if it sized right for your brake cylinder.

The brake cylinder has a plug in the pressure head above the valve mounting cast plate. This is where the T comes off for the HSRV. In the other end of the T we put a brake cylinder pressure tap so that we can monitor cylinder pressure during the single car test. Cylinder pressure readings are essential for monitoring how the HSRV is lifitng and setting in service. You can mount the HSRV anywhere around the cylinder where it will be accessible. Don't make the piping too long or you'll adversely affect cylinder volume and thereby pressure.

The brake cylinder should also have some side taps for piping the J-style slack adjuster. If you don't have the J, you can just plug the hole(s).

The components - cylinder, valve, slack adjuster, dirt collector and HSRV should be COT&S'd every twelve months according to AAR Standard S-045.

All of the best,

I operated P's when I was car foreman at Steamtown Foundation 20 years ago. Steve's explanations are the best I have seen, all I have to add is that originally there was an exhaust choke hung by a chain attached to the assembly, that choke was sized to the cylinder size so that the exhaust rate was uniform if the train had differnt sized cylinders in it. They were long gone by the time I got to Steamtown, I found out the sizes in an ancient O&MI Wabco manual, and put some new ones on. I wouldn't be surprised if they are gone again in Scranton.

Sorry, I have no idea where my manual is right now, but perhaps someone out there has another one.

Steve Z

Mr Z:

I'll have to take a look in the files ... I'm pretty sure that 14" chokes are sized 3/16, but I'm not sure beyond that ... I'll post if I find the sizings.

Thank you for the responses to my inquiry. I have received the information I needed and appreciate all of the help. (Thanks to Steve and others!)

Pat Connors

This discussion got me rethinking something I had posted earlier. On the A-1 Tornado thread, I had suggested having someone offshore, like the Chinese, build some simple generic coaches for tourist excursion service. My thought then was equipping them with ABDW freight car brakes. I know that ABDW does not allow for graduated release.

Is there something better out there, yet still simple, that would be appropriate for passenger service? I'm not talking high speed service here, maybe up to 35 or 40, whatever the event recorder threshold is.

Not that I have an immediate need, but the information might be useful to someone, now or in the future.

A 26C control valve is quite standard on passenger equipment today. I belive that the Grand Canyon is using quite a few of these on their passenger fleet.

We run PM, because it is part of what we portray, like plain bearings and steam. But if one is looking for a good reliable valve for slow-speed service, it is pretty hard to beat a 26C system or AB derivative. 26C will give one more precise handling, but an AB derivative is more than adequate for excursion service. Both are cheap to maintain and install. The key is a properly designed installation in order to render the correct braking effort.

On EDM's note, we have in design a B&M Commonwealth-style truck knock-off that would look like a plain-bearing passenger truck, except that it would have roller-bearing CJ33's (or MW 36's) in imitation plain bearing journal boxes. The idea is that a tourist line with clapped out trucks could install twelve-inch centerplates on their carbody and roll two of these trucks under it for new running gear. Brake rigging layouts could be accomodated for whatever brake system the line desires - cast/low-friction or high friction shoes. Stay tuned ...

Sounds like a really good concept. Any thought of providing for a Wabco-Pac type truck-mounted brake cylinder? That would keep the body brake rigging very simple and also elinminate have to scare up $200+ 18" cylinder cups....

Howard P.

Howard:

That's an interesting concept ... The assumption so far was that if a line was going to go with the retro-design truck, it was probably going to go with a modern brake system as well. 18-inch cylinders even challenge the knuckle-draggers among us at COT&S time. I hear that the packing cups are unobtainium ...

Steve,

My thought was (is) simplify things; especially if the brake system is a refitted AB-variant, and the trucks are new-build. The Wabco-pac setup would easily accomodate comp shoes, which are more available these days.

I think Bill Raia at Mid-Continent has converted a few wood cars to AB systems.

Yes, the 18" cups are now made out of that typical old train substance, "unobtainium". It sure hurt last year when we found an 18" cup (new) stored in a baggage car had been partially consumed by rodents.

Howard P.

I am trying to imagine the WABCO-pac system within the structure of the current design ...

Comp shoe conversion is not a problem. If the car's running gear is clapped out, chances are the rigging is too. Plus, the conversion of existing levers to the comp shoe ratio is rather easily done.

I was gazing under a brand new centerbeam the other day and was intrigued by the "hook-and-loop" rigging utilized in place of pins and clevises. There have been some clever, durable designs in freight car development that could be harnessed by our industry in the prolonging of our "Mixed Train, Daily".

I have a copy of instruction Pamphlet # T 5012 of Febuary 1908. This was in turn a reprint from January 1904.

THE QUICK-ACTION TRIPLE VALVE

copyright 1904 by the Westing house Traction Brake co.

I can copy and send out a copy to whover wants one.

Dave Wantz