can't help you with the coloring, but that's a interesting photo. I bet this is one of the reasons that steam was kept in 'reserve' in some roundhouses as long as they were allowed. Diesels won't hack it in flood waters for obvious reasons.
All that said, I've often wondered how much the crews and shop folks hated seeing steam locomotives running in high water. They're hard enough to keep lubed and rust-free in
normal conditions, let alone in several feet of water!
-Lee
Flickr photo set of my On30 layout