wade...
I made a little written record of your set of questions, thinking of them as pretty much a "word game". Perhaps I could answer one or more. But, not really. I've read a lot about the narrow gauge, here in the U.S, and elsewhere. The end result is that I might get one out of four of those right.
Believe this? George Hilton and I belonged to the same "Bachelor's Club" in Palo Alto in the 1960's. Hoping he is not watching this, I have to report that he is pretty much a pocket protector person. But, if you want to hear about baseball scores from the turn of the former century, he is the genuine authority.
Well, one little thing: My wife and I spent a month exploring Britain, several years ago. We started by taking the overnight train from London to Inverness, and then worked our way south. (I had gotten BritRailPasses for us, which are great.) And, finally, the point of my story: Somewhere in Wales, we had to transfer from the regular train service, to a narrow gauge. (I've really looked for the name, but can't find it.) (LLianfair??? In Wales, they don't spell things like we do.) At any rate, our BritRail passes were accepted on this steam powered, 20" gauge railroad. It was wonderful.
Bob Keller