Gee whiz! I would STRONGLY consider replacing the whole motor/chassis with one from a Lionel 18713 or similar. That's MUCH easier than what you're proposing, and would yield better results.
I would probably paint the driving wheels (and especially those cheap aluminim rims!) a dark grey to match the original appearance. (You could probably slide a grooved piece of paper or cardboard behind the wheels to keep paint off of the chassis.) Add a little weight to the top of the L-shaped metal plate between the steam chests, and you would have the best running 1062 on the planet! Think about it!
