When I saw the Canobie Lake engine some years ago, (in fact I rode the cab with the engineer...you sit side by side in the front of the tender) it was a conventional steam locomotive built by Crown Metal Products. The fuel was propane, but other than that, it was a similar design to all the other CMP amusement park engines in their various sizes. It most definitely was NOT a "fireless" type steamer. Propane was used because of its ease of operation and cleanliness in a park atmosphere. Many small scale "live steam" locomotives operated by hobbyists (especially in areas where coal is not easily obtainable) use propane to fire their models. It's virtually smokeless, produces no soot, cinders, or ash. When you're done running, you just turn off the burner, like your gas grill at home! Of course some of us prefer the smoke, soot, and smell of a coal burner... but for an amusement park operation, propane is more practical. As far as inspections, I would suspect that any "pressure vessel" over a certain size, and especially hauling people in an amusement park, would be subject to annual boiler inspections by both the state and the insurance company which covers the park rides. At least this is a "real" steamer, not a replica with a gasoline motor, or a "diesel" replica, as most parks have.