I think Steve we have been beaten to the punch with moving 3d puzzles. Their are quite a few RC and voice activated ones.
http://thumbs4.ebaystatic.com/m/mk5T...Hdr-NA/140.jpg
Heres my addition to the diesel loco and a carriage. I have shown some but not all of the surface burn detail. I don't bother modeling the surface burn just leave it as a sketch in the model.
Next up is a huge steam train with tender.