Minimum radius for O scale kadee couplers

Model Railroader General Discussion (Model Railroader)
1

A representative from Kadee informed me that the minimum radius for its couplers in O scale is 27 inches. However, in the OCT03 MR magazine, there’s an article: Grand Scale, Compact Space, in which the author, Richard Cooke, reports having a track radius of 24 inches in his staging area.

I’m planning a layout in a similar sized room as him, but was planning on making the radius 36 inches all around. However, at 24 inches, I could squeeze in an extra spur or two. Any information on minimum radius for Kadee couplers in O scale will be appreciated.

One thing; his is a switching layout and as such he doesn’t have long cars or locomotives. Perhaps this is a determining factor?

Dave Vergun

2

My NMRA data sheets book provides for determining minimum radius based on the distance between the pivot points of the coupler and the coupler swing angle from side to side. For a 10 inch distance the coupler swing needs to be 12 degrees for a 24" radius curve. For a 12 inch distance - 15 degrees. For 15 inches 18 1/2 degrees. The same method is used for the truck center distance and truck swing angle to one side. The method by the way uses actual inches and is independent of scale. Although of course a ten inch distance in HO is 73 scale feet and 40 scale feet in O.

Since your are pushing the limit here, a trial set up might not be a bad way to go.

Enjoy
Paul