So anyway I've designed resin chassis to work with these concepts, what shut me down was that the designer at Shapeways designed to size, not practicality, with the narrow nose width. I've seen this before in several models that work backwards from a 'perfect scale' rendering and then try to jam a mechanism in in. You need to figure out your mechanism before you design your body as just a rather minor dimensional tweak can make it feasible or make it impossible. Expecially on sills, coupler pockets, interior clearances.
My all time winner was the Alco MRS1 shell, I got it to work, but almost shattered it getting it on a chassis.