Has anyone had recent success with obtaining the older style brake cylinder packing cups, commonly called "WABCO" style cups? Not the more modern style used with the U series of brake cylinders that snaps over the groove, but the conventional piston cup style. I have attached a photo of pc#68580, the 12" version. We are looking for these in 8, 10 and 12.

Modern type "PC" piston cups such as you can get from numerous hydraulic/pneumatic supplies are not quite right. They have a more abrupt radius at the heel of the cup and tend not to seal as well.

Hi Jeff,

We may be able to help you.

If you're interested, please contact me at erich.armpriester@strasburgrailroad.com, or 717-687-8421, ex. 157.

-Erich

Hi Jeff:

I have had excellent experiences with custom-made packing cups from C.W. Marsh, Inc. in Muskegon, MI (http://cwmarsh.com/) to dimensions and specifications provided.

This firm was recommended to me by well-known airbrake expert Dave Garcia (who has sadly passed away) a number of years ago and they have produced packing cups for several projects involving National Pneumatic piston-type door engines as well as packing cups made to fit the brake valves in streetcars from Oporto, Portugal (which were made in STCP's own shops and unique to these cars). The cups C.W. Marsh provided for these projects to date have proven quite reliable and we had frustrating results with the Oporto brake valves prior to obtaining the packing cups Marsh fabricated.

Hope this helps. Good luck with your project.

Best wishes,
Matt Nawn

You can also try contacting Pittsburgh Air Brake Company (PABCO) http://www.pabco.biz/home. I have purchased 10" Westinghouse cups from them in the past for use on street railway equipment 1926 vintage they had them in stock. Worked out great.

I've posted it here a couple times. Multi-Serve a Buncher company in Leetsdale Pa. They can literally service almost any valve you have. I never seen so many test stands in my life! They are AAR certified. And they do a good job.

Hi Jeff, the Westinghouse Air Brake packing cups in the 68500 series, like shown in your picture above, were available from normal WABCO parts sources. Most sizes were a stock item until a couple of years ago when they went to Made To Order (MTO). They were made by the Wabtec Rubber Products, 269 Donohoe Road, Greenburg, PA, 724-838-1317. I have had needed information about the status of WABCO rubber products in the past and had success calling the rubber plant directly.

Originally Westinghouse Air Brake used leather cups and the 68500 series rubber cups were a direct replacement. However, the leather cups were used with an expander ring that is not used with the rubber cups. If you look at the iron piston you should see a grove in it where the expander ring was located. As I recall the ring was about 10 gauge spring steel wire rolled to a ring with just enough gap at the ends to get it installed. CW Marsh is an excellent source for leather cups, but you will need to come up with an expander. The advantage of leather is that it has an almost unlimited shelf life. As I recall the rubber cups have a 5 year shelf life. Both cups would be used with the AAR brake cylinder lubricate. Keeping the rubber cups in a zip lock bag with a little Armoral added will extend their shelf life.

Please let us know what you learn. Keeping track of suppliers of railway parts to museums is a never ending challenge.

Thanks,
David Johnston

Dave, thanks as always for the great technical advice.

I have had mixed results with WABCO rubber products. In some cases they have been able to help out with short runs but at other times they had lead times or minimum orders that are unworkable. The phone number you posted is the phone number that I last called so I think I'll give them a call during the upcoming week and see what the deal is.

It is also good to know that some of the service shops might be able to supply these in small quantities off the shelf.

At one time, there was a very active Parts Committee with ARM (now HRA) and it seemed like every year there was a group effort to have some rare part made in bulk and then apportioned to the various railway museums.

Regarding leather cups and shelf life, it raises the question: if rubber cups have a shelf life of 5 years, how long is their "shelf life" when they are inside of a brake cylinder?

I also wonder which would be superior in an old brake cylinder that has some pitting of the walls, leather vs rubber?