Not to throw a big 'ol bucket of cold water on this, but things can go horribly, terribly wrong. I can't imagine that anybody, anywhere, had enough liability insurance to cover this one truck move of a locomotive:
http://www.local12.com/news/local/story ... G7Xzg.cspx
That was last May. It came loose from the tractor. A GE 80-tonner moving at 65mph or so obviously has a lot of kinetic energy.

Alan's comment about loading rules and clearances is absolutely correct; what floors me is the the equipment I'm seeing moved on top of flatcars, on its own wheels, despite that. Reading 2100 as a flatcar load headed to Tacoma? Yup.

I just finished working with a railroad museum getting a 1941 58' six-axle PRR flatcar moved via highway, the Buckeye trucks alone weighed 10 tons each and were separate truckloads and detached. As the brake rigging was gone, a rail move was out of the question. Other than having to get real creative on the unload process using multiple backhoes, went quite well for them.

We've participated in the movement of several trolleys as flatbed loads, those are almost routine. The Roundhouse museum in Savannah DOES have their own trailer for such equipment moves and it got used to move the Savannah car from Altoona to Savannah. That's a roll-on/off trailer. That's been a real handy thing to have for them because they do not have live rail to the museum anyway, which helps justify the effort.