As a kid, I remember a train that would circle the old Elitch Gardens at 38th & Tennyson in Denver. The year before they closed the ride permanently, I rode it with my parents because I was only 5. For years afterward, I had hoped they would re-open it, but they never did.
The magic of the Elitch railroad lives on in places like Tiny Town, Lakeside and a little park in Loveland, Colorado where the Buckhorn Northern Railroad continues to delight riders to the tune of 75 cents per round trip.
If anyone else would like to post their memories of "less than 2' gauge" or links to their favorite park railroad, they're welcome to contribute!