3-piece electric locomotive Dm3 from Swedish state railways.Right after the Second World War, the demand for Swedish iron ore increased dramatically. Suitable locomotives were needed for transporting the heavy ore trains. The Swedish state railways (SJ) ordered the first DM series dual locomotives, the first of which were delivered in 1953. Each of the two locomotive parts was equipped with a reactive shaft drive and four coupled drive axles with spoke wheels. Five DM locomotives were equipped in 1960/61 with the newly developed Motola 1960 spoke wheels. These powerful locomotives were able to transport ore trains of up to 3,200 tons via the sophisticated Malmbana LuleÃ¥âKirunaâNarvik. The heavy trains consisted of 52 mineral wagons. Each of these 3-axle wagons had a dead weight of 20 tons and was loaded with 80 tons of ore. At the end of the 1960s, the increase in tensile weights to 5,000 tons was implemented. For this purpose, some machines were extended by another, driver-free, four-axle center section and called Dm3.This text is machine translated.