At one time, Hawaii had a network of railroads on each of the larger islands that helped move farm commodities as well as passengers. These railroads were all 3 ft (914 mm) narrow gauge for the majority although there were some 2 ft 6 in (762 mm) gauge on some of the smaller islands – standard US gauge is 4 ft 8 1⁄2 in (1,435 mm)). The largest by far was the Oahu Railway and Land Company (OR&L) which ran multiple lines from Honolulu across the western and northern part of Oahu. The OR&L was an important player moving troops and goods during World War II. Traffic on this line was busy enough that there were signals on the lines facilitating movement of trains and wigwag signals at some railroad crossings for the protection of motorists. The mainline was officially abandoned in 1947, although part of it was bought by the US Navy and operated until 1970. Thirteen miles (21 km) of track remain and preservationists occasionally run trains over a portion of this line