Malmbanan
In 1915 the Iron Ore Line (Malmbanan) was electrified between Kiruna - Riksgränsen by Swedish State Railways on the standard gauge network at 15 kV 15 Hz. with power coming from the new hydroelectric station at Porjus. To enable the railway network to use converters from the national electric grids with its 50 Hz the frequency was changed to 16,7 Hz