All Harpur locomotives (excluding the little 7-1/2" gauge ones, of course) were 3' gauge. Not too many standard gauge operations in amusement parks, although one or two exist.
The second Astrworld trainset was sold to Gary Norton for use on the Silverwood Central, but only the coaches were ever used there (and still are). The locomotive was sold from there to the party in Laramie, and has since been moved to Durango under private ownership.