I'm doing research for a project on steam locomotives, and I don't have extensive knowledge on the subject. I have a question. In a passenger train with a steam locomotive, was it possible to access the locomotive (the cab, etc) from the cars which carried the passengers, while the train was in motion? Would the answer be the same for cab-forward locomotives as well? Thanks.
Only engines I know for absolute sure that were setup to do this were LNER Pacifics such as the Flying Scotsman, Mallard and others of the A-3 and A-4 class. They were equiped with what was called corridor tenders so crews could be changed while underway on trains such the non-stop London to Edinburgh express trains. In photos you can see the door and passenger car type diaphram on the rear of the tender. Other photo is of the corridor in the tender itself.