Rio Grande Southern Railroad

The Rio Grande Southern Railroad (reporting mark RGS, also referred to as "The Southern") was a 3 ft (914 mm) narrow-gauge railroad which ran in the southwestern region of the US state of Colorado, from the towns of Durango to Ridgway, routed via Lizard Head Pass. Built by German immigrant and Colorado toll road builder Otto Mears, the RGS operated from 1891 through 1951 and was built with the intent to transport immense amounts of silver mineral traffic that were being produced by the mining communities of Rico and Telluride.

Source: Wikipedia — Rio Grande Southern Railroad (CC BY-SA 4.0)