HO Railroad Well Car designed to work with 18" curves and look good next to readily available inexpensive rolling stock like I own.
It is simulating a 57 foot well car and will hold either a 44 or so foot trailer or 34 foot or shorter container or two. I think a regular 28 footer on bottom and 40 footer on top would look well.
I have my trial model on order and will post pictures as soon as it is received.
With my more simple initial design in WSF I drilled a hole and used a screw to mount the truck then superglue for the Kadee coupler housing.