Not sure I'll be able to get retractable windows on there, don't think I have the patience to attempt it. And without any good close-up pictures of the prototype, I'm afraid they're going to be closer to the ones that Lionel put in the Centipedes (though I have moved the divider between the sliding window and "vent" window closer to the front than they did). Running a divider down that piece, with one half tangerine, and the other silver may not be something my eyes are up to anymore.
This is the best pic I've got of one of the windows. It's down, mine'll be up. As I mentioned, not sure I can nail that line dividing them and the 2 colors.