Rolf Wiso's locomotive database
Rolf Wiso's amazing database can answer a lot of questions. The history of almost any specific locomotive, i.e. Depot allocations, boiler changes, rebuilds can be found here. http://de.geocities.com/rolfwiso

Well, it looks a stunning piece of work. But alas EUR33 to find out about 10-12 locomotives seems a bit expensive to me. Maybe next year :8) John