Kevin,
I guess I should point out that the only large power that ever ran the Silverton under the Grande was a K-37 #492 which yes only went to Rockwood, but the Grande did move the 481 to Durango in 1968 because they were going to do studies on using it on the Silverton branch--so they knew it was possible they just never followed through. I am glad they did have the vision because it allowed the D&S to get the 481 which was kept in good condition over it's 13 yr slumber in Durango from 68 until 81 when it was restored.
William
aka drgwk37