The Iron Ore Line (Swedish: Malmbanan) is a 398-kilometre long single track railway line in Sweden. The first section of the line opened in 1888. The trains hauled by Iore-class locomotives are 68 cars long and weigh 8,600 tonnes.
https://en.wikipedia.org/wiki/Iron_Ore_Line
Photo credit: Kabelleger / David Gubler/CC BY-SA 4.0, https://commons.wikimedia.org/wiki/File:MTAB_IORE_101_%2B_119_Katterj%C3%A5kk_-_Vassijaure.jpg