My CN boxcar keeps uncoupling at the same spot on my layout. Got out my trusty NMRA gauge and the coupler is too high so I take it apart thinking fairly simple to get it lower but it’s not all that simple. It would appear that filing off some material on the truck cross braces is only solution. Anybody out there routinely calibrate coupler height that can give me some clues?
Cottage Grove Grainger
How about installing one of the Kadees with the offset knuckle? They have them to both raise and lower the coupler knuckle without having to modify the mounting for the coupler.
The #22 might do the trick?
http://www.kadee.com/htmbord/page67.htm#HO#22
How is the overall height of the car? If the roof is higher than the rest of your boxcars, then filing down the truck mount is probably the right thing to do. Another option is to cut out the coupler pocket and buy some Kadee “draft gear boxes.” These are very inexpensive, and fit the couplers perfectly. You can glue them on or drill and tap for a 2-56 screw. To lower the coupler, all you need is a thin piece of styrene for a shim.