I too was at the York RR museum in England back in the mid-90's. I'll have to dig out my pictures and compare to yours. I don't remember the boiler cutaway display. I believe there's a similar display at Steam Town in Scranton, PA.
I love the filigree work and other touches on the castings of the stationary engine, function AND form. Back in the days when craftspeople took pride in their work. Nowadays if it isn't necessary, it's left out/off.
While the York RR museum was great, I don't really think I appreciated it back then. I have since acquired the steam disease (thankfully no ones developed a cure and little $ is being spent on research into that ;D) and really appreciate the design and ingenuity of the designers/engineers/craftsfolks of our past. No computers, lots of trial and errors (many catastrophic), pencil, paper, log/trig tables, slide rules, seat-of-the-pants engineering.
Mike