During a recent layout tour I hosted someone told me of a manufacturer that produced couplers that had spring loaded shafts so when the cars were taking tight corners the the shafts lengthened and then retracted by the use of springs in the shaft. (Not talking the standard coupler spring).
I beleive it was in the U.K. but not sure ? Does anyone have any information because I have since lost my notes I took! [#oops] I’m still searching Kadee’s web site but have not found them as yet.
I beleive they were the horn style coupler but any info would help!
In HO, the only one I’ve seen that projects and retracts on corners is the ones that Bachmann installed in their model of the Acela. Walthers markets a swing coupler mount, but it doesn’t lengthen:
In European HO, there’s the NEM 362 shaft that allows close coupling with wider separation on curves and Kadee does make a series of couplers that will plug into the shaft. However, you don’t get true close coupling with Kadees since they need slack to uncouple.
I have a Roco Austrian ‘Crocodile’ electric locomotive that I run occasionally (when I want to turn my Sierra Nevada into the Alps, LOL!) that is a very sweet runner. It has the NEM shafts on the locomotive that appear to be sprung as you have described. I have installed a Kadee #17 NEM conversion coupler into the NEM shaft, and it works perfectly. This is the shortest shank of the Kadee knuckle couplers available for conversion.