As many of you may know, I'm quite of a "park train" enthusiast having grown up around and now more or less in charge of our local 2 foot gauge excursion line using a CP Huntington. In addition, I've ridden many miniature railroads in the DC area, some not running anymore, as well as up and down the east coast. We use it as a scenic excursion, not a "amusement ride" and these trains are not "amusement rides".
The Arizona & Pacific RR in Arizona is a private line, and the owners, who are VERY good people and well respected in the hobby. Check out their webstie below. You can easily spend hours reading. I closely follow their project updates and the entire site.