Patrick,
I have a pair of the Yoder cars that I converted to 3 rail. I put Atlas trucks on them. They look like any other 3 rail car as far as wheel sets and couplers are concerned and they track very well. You can see them any time that you'd like.
Recently I converted a Yoder dry ice car to 3 rail and it looks pretty good also.
Sorry that I missed your evening running trains. Merry Christmas.
Norm