John,
The photos exist of 3' gauge through Glenwood Canyon albeit on Broad Gauge ties. The Aspen Branch was laid as 3' gauge and, like the rest of the line, later converted to compete with the onslaught of the Colorado Midland into heretofore 3' gauge country.
There are photos of the opening of the Aspen Branch showing 3' gauge equipment there.
I believe that Mark Greska might be attempting to utilize the track for another tourist operation (or even as a connecting commuter Railroad) as the track is now lying fallow between Glenwood Springs and Woody Creek. he might even want to keep it broad gaauge and connect with Amtrak at 13:30 and 15:15 each day. You might want to ask him.
Rick
Rick