OK found out it was Standard
It is listed as standard gauge in "Colorado's Mountain Railroads" by Robert LeMassena
thanks for the replies..yes there is little history of it...other than what I we found in a wondeful journal issue by the Grand Valley Historical Association back in 2004 on Logging in the Valley. There was extensive logging all over the region and much of it was wildlands work done by independent woodsmen who had their own teams, cut in the summer on areas marked by the Forest Service and 'decked" or stacked the logs and then pulled them to either local portable mills or the bigger ones like the Middle Park Mil at Fraser...and another large one at Tabernash. The Denver Northwestern and Pacific, later the Denver and Salt Lake RR which built the Hill route over the top of the Rollins pass and later the Tunnel ran from Tolland over the top and thru Corona and Arrow and down to Fraser and on to Tabernash, that is the extent of our route and work , I am making most of the structures and the route is made by a master at teh craft of digital RR work in Italy.... we are finishing up a winter version just now and thinking of adding this small short line ..which we now know was SG. thanks for the replies and it is nice to 'meet" someone from the Valley. It was very hard finding photos and data on Fraser and Tabernash and we are still looking for more... thanks again guys.