The Magma Arizona Railroad (reporting mark MAA) was built by the Magma Copper Company and operated from 1915 - 1997. The railroad was originally built as a 3 ft (914 mm) narrow gauge line, but was converted to 4 ft 8 1⁄2 in (1,435 mm) standard gauge in 1923. Originally headquartered in Superior, Arizona, the company primarily hauled cattle and copper on 30.2 miles (48.6 km) of standard gauge track to and from the Southern Pacific mainline in Magma, Arizona, between Florence and Queen Creek. The Magma was the last industrial short line railroad to use steam power.