Methinks there are rivets on the smokebox, while I wouldn't be surprised at welding on a newer loco. According to Wikipedia, it's real, GWR 2884 class #2885. *Lunatic*, n. One whose delusions are out of fashion.
2885 is a member of the Great Western 28xx 2-8-0 8F Heavy Freight Locomotive Class. It is a 'guest' locomotive that is presently out-based on static display at the recently restored original Birmingham Moor Street station>>.