Kelly Choda wrote "Thirty Pound Rails" in 1956, in it he stated..
"30 Pound Rails- - - The first rails made in Colorado weighed 30 pounds to the yard. In 1882 the Durango-Silverton route was laid with rails rolled in Pueblo. The first rails used by the D.&R.G. were imported from England and Belgium."
Robert D. Turner in his book "The Thunder of Their Passing" writes "40 pound per yard was laid between Alamosa and Antonito; between Antonito and Chama 30-pound Iron rail used, with similarly sized Steel rail between Chama and the lonely passing track of Carracas and both types for the rest of the route to Durango"