Really not much room except externally look at #53. Forgot Mamod made trains but the thought of a handbrake type appeals. Memory not that great may have been the other forum but i did ask the question of engine self starting and it was classixs (member of this forum) who came up with the answer from memory it was a single acting cylinder stationary engine make i don`t remember but certainly not British but again i don`t remember if he explained how. So classixs if you remember it would be nice now if you came fwd and gave us the answer. Still cleaning.