3-part electric locomotive Dm3 of the Swedish State Railway.

■ For the first time in original design with spoked wheels
■ Free-standing lines and handrails
■ Close-coupled locomotive parts
■ High traction power because of two motors

Immediately following the Second World War, the need for Swedish iron ore drastically increased. For the transport of this heavy iron ore, suitable locomotives were required. The Swedish State Railways (SJ) ordered the first double locomotives of the Dm series, of which the first engines were delivered in 1953. Each of the two locomotive parts was equipped with a blind shaft drive and four coupled drive axles with spoked wheels. In 1960/61, five Dm locomotives were equipped with the newly-developed “Motola 1960” spoked wheels. These powerful locomotives were able to transport ore trains of up to 3,200 t over the demanding “Malmbana” Luleå–Kiruna–Narvik route. The heavy trains comprised 52 ore wagons. Each of these 3-axle wagons had a tare weight of 20 t and was loaded with 80 t of ore. At the end of the 1960s, the train weight was increased to 5,000 t. For this purpose, some engines were extended with a further, four-axle central part without a driver’s cab, and these were designated as Dm3.