NMRA Specs

Model Railroader General Discussion (Model Railroader)
1

I’m trying to date some of my older locomotives. Did all the manufacturers adopt the RP-25 wheel spec at the same time? Does anyone know when Mantua and Rivarossi went to the RP-25 wheels?

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

2

RP-25 is a recommended practice. The NMRA Standard for flange depth is .035 inch.

The Japanese brass builders went to RP-25 almost as soon as it was published. Mantua and other American manufacturers followed suit. The European manufacturers, including Rivarossi, held out with the European pizza-cutter flanges well into the '80s - two decades after I bought HOj tinplate cars with RP-25 wheels.

I’m not sure when Rivarossi fell in line.

Chuck (Modeling Central Japan in September, 1964)

3

There are still cheap train set cars out there with very crude looking pizza cutters…

As Chuck mention there is no standard just the RP.

4

If anyone knows when RP-25 was published, that might be helpful to know, if many manufacturers follow it soon after it was out. If you can track a model build date, it may be useful.

5

I recall waiting excitedly for the RP25 wheel sets( Athearn)trucks actually) in the early 60s Athearn was among the first to adapt flanges to RP25. The reason I couldn’t wait is because I was all for the more to scale flange and couldn’t wait to start the change over from those awful sprung trucks with pizza cutter flanges of the time to the RP25 wheels…

A fun tibit… A lot of old heads said those RP25 flanges was to tiny and will never stay on the rail.

6

My 1972 copy shows an issue date of August 1961. It’s not marked as an update.

Enjoy

Paul

7

I e-mailed NMRA and received a quick reply. The RP25 wheel profile went into effect in 1963. I attached the PDF to my Google Drive.

https://drive.google.com/file/d/0B7gZp9MPvrm3Rmg0WWtNYWFZdzg/view?usp=sharing

Thanks for your input guys!

Mel

Modeling the early to mid 1950s SP in HO scale since 1951

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California