Anonymous says:

You’re probably using Kadee couplers on your rolling stock which are the most common knuckle couplers out there. Go to the Kadee webpage (just Google or Bing search “Kadee” to get there) and you should be able to find a conversion table that will list the manufacturer of your locomotives and which type of coupler kit you should buy.

If you don’t know who made your locos, it essentially comes as a ‘hit or miss’ fix as far as coupler replacement is concerned. Kadee is pretty helpful so if you can send a fairly detailed e-mail and maybe even a photo describing the coupler mounting currently on your locos, they should be able to help.

Be forwarned that some conversions require you to do some fairly precise cutting and adjustments on your equipment so if you aren’t that handy or don’t have the right tools, a local hobby shop may do the conversion for you (for a fee, of course).

Hope this helps.

Geof