I disagree with that, as there are any number of "operating steam locomotives" around the world, yet the average person has no clue how they actually work. For example, during our display time in Owosso, MI at the big Train Festival event in 2009, we had the cab of 4449 open for public tours, while she was fired-up. We could fit 5 to 8 people in the cab at a time, and during one of the many question and answer periods, as different folks walked through the cab, I was explaining what the different valves & controls were, showed them the fire through the sanding peep hole, and how much fuel and water she typically used pulling a normal passenger train. One lady asked, "What is in that car right behind us?", and I explained how the tender is draw-bar connected to the engine, and how much fuel oil and water it holds when full, etc., etc., etc.. A few more questions about oil vs. coal, and suddenly a man asked, "What's the water for?"! I was stunned! One of the few times in my life I have speechless, and the other folks in the cab began to laugh, on top of that. As I tried to regain my composure, the guy got mad, said something unkind to the rest of the folks, and pushed his way out the exit side , and left. One younger women, with her two kids, said thanks, and offered "Don't worry, it takes all kinds!", as that group departed.
My point is, a fully dissambled steam locomotive, with the boiler off the frame, and all the internal components of both the boiler/firebox and engine running gear full exposed, is much more able to be a VERY informative teaching tool, especially for those who have really no clue.
We've all had those questions. Our center-cab diesel and our 0-4-0T steam locomotives were sitting side-by-side once. With smoke and steam swirling around the steam engine, and the diesel grumbling away, a gentleman strode up and asked me, "Now, which one is the steam locomotive?"
Sure, I was shocked. But I also understood that this 30-something had never seen a steam locomotive in his life; maybe had never even seen a diesel.
Instead of laughing at him, I took the time to explain the differences to him. Instead of having someone leave angry, I enlightened him, and perhaps created a new fan. That's why an operational locomotive is more instructional: It invites questions, as opposed to a cold, dead boiler with the interior surfaces painted red, blue and white and a sign that says "crownsheet."
Sure, cut-away boilers have their place. But if I'm going to explain the history and operation of an injector, I sure as heck would want an operational one in front of me to show someone how it works. So they can see what it looks like to prime it; to hear it even. If I want to show how we check the water level, I want them to be able to see what the water looks like inside a water glass, or see what happens when I open the tri-cocks. Having a non--operational water glass with the interior of the lower half painted blue doesn't teach much.
If I want to teach someone about the pure power of steam, a cut-away boiler with the space above the crownsheet painted white isn't going to be nearly as instructive as opening the blowdown valve on an operational engine, feeling that explosive blast in your chest as the white plume jets out a hundred feet from the engine.
Your statement that "there are any number of "operating steam locomotives" around the world, yet the average person has no clue how they actually work" seems to suggest that you feel you could educate more people about steam if there were fewer operational engines; that they aren't very helpful. Perhaps it is the people operating these engines that need to think about how to teach better, and not suggest that dead, cold boilers are better teachers than operational engines with crews willing to share their knowledge, and not laugh people out of the cab.
