Several people told us that if we were anywhere near York we should definitely go to the National Railway Museum. So off to the museum we went - it was free, but we had to pay an 'all day' fee to park the car. I'm glad we started in the morning because we were there most of the day. So the car park fee wasn't wasted :)
It's a huge collection, of trains and everything associated with trains and railways. They have a huge room full of shelves loaded (in an orderly way) with models, signs, clocks, tools, seats, timetables etc etc. There was a big research library for the train fanatics. The children's playground was a joy for parents and grandparents as well as children. There was a viewing deck with an electronic timetable displayed so that we could see the real trains going past. We could see the Flying Scotsman in pieces in the (very clean) workshop, undergoing a complete restoration.
We saw a replica of Stephenson's Rocket, and dozens of other trains of various ages including royal trains. There were a lot of people around but in such a big space that wasn't a problem. I'm glad we went but I think I've seen enough trains now.