The original ambitious plans of Denver and Rio Grande Railway founder William J. Palmer projected a north-south narrow gauge route from Denver to Mexico City following the course of the Rio Grande for much of the distance.: As early as 1878 it was reasoned that such a route would not be possible, but Palmer did receive a concession in September 1880 from the Mexican government to build a different north-south line, the National Railroad of Mexico. Initially planning to access the Territory of New Mexico via Raton Pass, a route that the AT&SF had already begun grading for the construction of its own east-west transcontinental route, the D&RG had to look for alternative routes to the south as its conflict with the ATSF festered.: The conflict eventually resulted in the D&RG shifting its attention to lucrative mining opportunities to the west. Palmer's dream of a road to Mexico City finally went glimmering but the line along the Rio Grande became the exotic southern extent of the D&RGW's famous network in the Rocky Mountains. Prior to the conflict, the D&RG had built tracks over La Veta Pass to Alamosa in the San Luis Valley.: By 1880 narrow gauge tracks were in place as far south as Antonito and the construction of a line towards Albuquerque was underway.: