This industrial line once connected a large and remote Phelps Dodge copper smelter located 30 miles from the Mexican border in Hidalgo County to the SP/UP mainline further north. The Hidalgo smelter was built in the 1970s along with the nearby company town of Playas for employees of the then new facility.
Following a move towards newer technologies and declining copper prices, the Hidalgo smelter closed in 1999 and laid dormant for several years until it was demolished around the time Phelps Dodge was acquired by Freeport-McMoRan in 2007. Meanwhile, the town of Playas was bought by New Mexico Tech and converted into a restricted training and research facility for the university's first responder and counter-terrorism programs.
Today, most of the tracks are gone but the right of way is still quite visible and marked clearly by the left over ballast, along with the Route 70 / Interstate 10 overpass and still used sidings by the UP mainline.