In step with the increasing ore mining, increasingly powerful machines were required for increasingly heavier loads. Today, the Ore Line is operated by the world’s strongest locomotive.
The ore traffic got off to a difficult start. When SJ took over the newly built Luleå – Gällivare line after the British company that built it, it turned out that the locomotives used were not owned by the English. The locomotive belonged to the manufacturer, and was not part of the takeover of the track.
SJ quickly sent up old freight train locomotives of the type G from southern Sweden. These were built in the 1860s, and far too weak for ore trains of 1,000 tons. You had to put both two and three locomotives in front of each train, and yet they barely managed.
SJ ordered new locomotives of two types. Ma locomotives, with a service weight of 76 tonnes, were used on the Kiruna – Riksgränsen section, and the lighter Mb locomotives with a service weight of 67 tonnes operated on the Gällivare – Luleå section. They had four driving axles and could pull significantly heavier loads than the old slightly G-locomotives.
But soon the ore trains became even heavier and in 1907 SJ ordered five new so-called R-locomotives, which had a service weight of 85 tonnes and five drive shafts. With 1,435 horsepower, the R locomotive was Sweden’s strongest steam locomotive, and could pull ore trains of 1,400 tonnes.
When the track was electrified, the R-locomotives also became redundant. Four of them have been scrapped for a long time, but the fifth is preserved at the Railway Museum in Gävle in serviceable condition.
The first electric locomotives were German-made Oa locomotives that could handle train weights of 1,900 tonnes. In the 1950s, they were replaced by Dm locomotives that enabled ore trains of over 3,000 tons, and when the three-part model Dm3 was introduced in the 60s, train weights of over 5,000 tons were achieved.
The world’s strongest locomotive
At the turn of the millennium, they were replaced by IORE locomotives from the Canadian manufacturer Bombardier. With a traction of 1,200 kilonewtons, they are the world’s strongest locomotives, and each train set – 750 meters long and with 68 carriages – transports 6,800 tonnes of iron ore.