This connecting line, the Arizona and New Mexico, was converted to 4 ft 8+1⁄2 in (1,435 mm) standard gauge in 1901.
Steam locomotives of the 20 in (508 mm) gauge system continued to operate, even after expansion of electric mine railways which captured a significant portion of the ore movement.
After World War I operations on the 20 in (508 mm) was sporadic, with the entire system being shut down in 1932 and mostly removed by the later part of the 1930s.
Several 20 in (508 mm) gauge locomotives and cars from the Coronado Railroad and associated copper mining companies survived into preservation.
Three locomotives were left abandoned on a hilltop until 1990, when they were removed over very steep terrain by dropping down a loaded truck reinforced with a cable attached to a bulldozer.