I don't know if it's a fallen flag or current, so I just decided to post here so more people noticed. I have a very clear recollection of a picture I saw at least 10 years ago. It was in a book, but I have no idea what book. To the point - It was an F-unit, notable for its eye-popping paint scheme. The top half was yellow and the bottom half was violet. The separation line had a slight upward wave on the front: a typical EMD paint scheme element. The letters UW were on the side. I believe the U stood for Utah, with the railroad name being Utah & Wyoming or maybe Utah Western. According to this page http://utahrails.net/utah-rrs/utah-rrs-list.php both names existed - in the 19th century. I have a disturbing feeling this engine didn't exist, but then how could I have seen the picture of it? And yes, I'm sure it wasn't a model.
Ya, that's definetely an eye popping paint scheme! It's funny you mention the colors, so close to Easter! Would make a good "Easter Egg Express"!
Right now, this doesn't sound familiar. Hmmmm..... Could it have been painted up for a special event/presentation? Which happens now and then. Boxcab E50