United States Potash Railroad

The United States Potash Railroad was a 3 ft (914 mm) narrow gauge railroad built in 1931 to carry potash from the mines to the mill at Loving, New Mexico where the Atchison, Topeka & Santa Fe Railroad had a spur that went out to the refinery to carry out the processed potash. The 16-mile (26 km) railroad was located at Loving, New Mexico, just east of Carlsbad, New Mexico, USA, and Carlsbad Caverns National Park.

Source: Wikipedia — United States Potash Railroad (CC BY-SA 4.0)