Uh, while not the exact subject, let’s not forget the Flying Scotsman (LNER), the Schools and King Arthur classes (SR) and the Great Western express locomotives. I believe all of them had a green livery. The London Midland and Scottish RY bucked the system, painting their locomotives crimson lake. I suppose that any steam locomotive that could burn garbage cleanly might be considered “green” in the current sense of that word.
Just a thought, David Meashey