Reverting back to hook & horn couplers?

[RobertInOntario]

Rob: at 15" radius, you might have to go for a longer Kadee. They make variants that fit the #5 boxes but are longer.
Also check the heights against the Kadee gauge.
Look for couplers that are not mounted level -- they change height as they are pulled out.
Do you have any abrupt grade changes? Long cars can unhook on these.

Thanks, David. I do have 1-2 longer Kadees. The LHS I used recommended these for locomotives. I did attach one of these to one of my coaches and it worked well for awhile, but now I think that is one of the couplers that is acting up!?

I still think this is part of the solution, as are the shelf couplers.

The layout is fairly flat -- I tried to work hard to make it this way. Still, there are some gradients at 1 or 2 of the turnouts where the track bulges up -- one of these is also just before some curves, so there is a combined problem (i.e. lifting up & down then swinging through a curve).

I'll keep plugging away at this !

Rob