"A gun is a.... I suppose the best way to describe it is as a miniature crossbow. It fires very small bits of metal called bullets, but with enough speed that it's impossible to see them in the air, and enough power that it will pierce your entire body." Not always - though a bullet left inside can be even more dangerous - but it was important to know when to truncate an explanation for clarity.

"Anyway, treating this train as a learning experience is a good way to look at it." It will, at least, be less frustrating that way. It outlines clear goals and can instill purpose. It's actually a very good idea.