Here is my Bachmann 2-10-2 project. The Bachmann K4 Delta trailing truck does fit, but you do need the file down the pivot thickness some. The 1st photo are my DM&IR 2-10-2 with GHQ side frame mounted on the stock truck. I plan on switching this for K4s in the future.
That Bachmann coupler on the pilot sure does take away from what is a nice looking engine. Anyone come up with something to replace it? MTL has nothing on their conversion page.