The San Manuel Arizona Railroad (reporting mark SMA) was an Arizona short-line railroad that operated from a connection with the Copper Basin Railway (CBRY) at Hayden 29.4 miles (47.3 km) to San Manuel. The SMA began operations in 1955, and ceased operations in 1999; the copper mine in San Manuel shut down in October 2003. There was hope the operation would return in mid-2012, and about a year later the railroad was acquired from BHP Billiton by Capstone Mining Corporation as part of the Pinto Valley Mine operation. But in 2016 Capstone idled the railroad.
Back in batter days, SMA RS-3 10 (originally Reading Company 521) and GP38-2s 17 and 16 (built by EMD in October 1971) are seen dropping a train off for the CBRY. (Hayden, Arizona – September 27, 1982) Russell Eslick photograph, Craig Walker collection