For air brake and steam piping on locomotives and railroad cars, schedule 80 "extra-strong" pipe (or thicker) is required. But what about the pipe fittings? Are 250 psi and 300 psi malleable iron fittings OK if they do not have "AAR" cast into them?

- Doug Debs
www.ggrm.org

For passenger applications 300 Lb. Schedule 80 pipe pipe fittings are approved in the AAR Standards and Recomended Practices as well as heavy wall copper as long as the copper fittings are brazed as opposed to soft soldered. Schedule 40 pipe can only be used for the 10" nipple coming out of the angle cock on passenger equipment if equipped.

For interchange freight applications AAR calls for Schedule 80 pipe with welded connections. Threaded pipe connections are prohibited.

I would not recomend the slip-on Dresser style couplings be used in any application.

The last fittings I saw with AAR cast in them were manufactured by the Stanley Flagg Company of Stowe, PA. I think they are out of business.

E.B. Levin

As I recall, the schedule 80 pipe fittings sold by McMaster-Carr have the AAR
designation. I think Grinnell is the manufacturer.

I worked for 6 years in industrial supplies. Grinnell pipe fittings were readily available. You might want to get a quote from some of your local suppliers, they are frequently cheaper than mail order suppliers like McMaster-Carr.

I am not sure threaded can be totally prohibited since all our angle cocks and glad hands are threaded. Socket style flanged connectors are still sold by Westinghouse air brake (and others I assume) - especially good in areas where a welder cannot get to the backside of a joint. Do not forget that fairly wide radius changes in direction are required, not a simple 90 degree elbow. Maybe 6-9 inch radius recommended?

Also I believe that threaded piping is allowed below a certain size, such as on retainer valves and lines.

Bob Kutella

Strato Supply in NJ can supply socket welded pipe fittings from stock.

I use McMaster Carr for AAR pipe fittings because their lead-times are very short,i.e., they can usually supply from stock next day delivery. Most of the local outfits I have dealt with do not stock AAR (Schedule 80) pipe fittings.