I picked up an inexpensive (and inoperative) Lionel O-scale locomotive at the York Train Collectors Association meet. Instead of using it as is, I wanted to give it a bit of a European WWII feel. It's not a truly historic example but representative of the locomotives one would find in Western Europe in the 40s.
The conversion was simple and used some plasticard, a couple toothpicks, and some scrap from a plastic model sprue. I think the results work great for a wargame table.