SJ Dm3

The series vehicles Dm3 the MTAB are electric locomotives that were built in the 1950s for the Swedish Statens Järnvägar (SJ ). They were used against heavy ore trains on behalf of the mining company LKAB. The operation and locomotives to LKAB subsidiary MTAB were issued in the 1990s. Officially, the triple locomotives are first referred to as Dm Dm Dm3, where it shortens were also called Dm3. Only since the takeover by the MTAB is Dm3 for the whole locomotive 's official designation. The three-piece locomotives were the most powerful electric locomotives in the world for many years.

History

There are three short-coupled, electrically interconnected locomotives. Each of the three parts has four coupled driving axles. They are connected to a position located in the middle of the locomotive blind shaft which is driven by two electric motors. The two outer locomotive parts each have a cab and an extra barrel. The two pantographs are also located on the locomotive ends; in operation, they are both ironed ( extended), and the middle part of locomotive is powered by roof lines. Was it originally possible, the end parts of a Dm3 individually to drive, this is going since the major renovation in the 1990s, no longer, because now sits in the middle part of the central control computer of the locomotive. The small m in the name refers to the way " Malm ", Swedish for Ore.

The origins date back to the beginning in 1953 procured double locomotives (Dm) back (later referred to as Dm2 ), which was a derivative of the 1'C1' series Da and originating from the 1920s locomotives on the Erzbahn should finally replace. 1957 orders and deliveries in 1960 has been a pre-series of three double locomotives from the second Dm series. These three Dm received from the factory a leader was loose midsection inserted, called Dm3. Therefore, these locomotives are numbered consecutively.

They wanted to go with a new ore cars, the type Mar, 65 car trains with 4,875 tons. The cars were a failure, the possible conversion of the other Dm the second series with other Dm3 never happened.

The third and last series of Dm was increased and heavier version, recognizable by the 1200 operation number. Of 15 double locomotives were built in 1961 and as 1201/1202 bis 1229/1230 numbered. Again, only double locomotives, as it still had no suitable ore cars, but finally wanted to replace the Vorkriegsloks in Südumlauf the Erzbahn to Luleå.

Mid-1960s it was clear that from about 1967 useful types of cars for 5,000 -ton trains are available. Therefore, in 1966 the in 1961 established as an option means parts for these 15 locomotives were ordered, delivered in 1967 and 1968, these 15 Dm3 are numbered sequentially with 1231-1245, but were not added to the sequence to the existing Dm pairs. This " haphazard " Numbering has never been changed. As a conclusion was made in 1970 a sixteenth heavy three-piece Dm3, which is numbered as one of the 1200s Dm3 continuously - 1246-1247 ( Dm3 ) -1248. And as a reserve even a real Dm 1249/1250. This is because it was found that due to the stability of the frame with a locomotive of the 900 Dm none of the 1200s could be replaced, as the older 900s were built lighter. The 1970 -built locomotives were the last electric locomotives with drive rod drive world. The 1200s Dm3 with the three Vorserienloks were then in 1970 the locomotives on the North circulation Kiruna -Narvik, while the remaining Dm2 transported the ore trains in Südumlauf Kiruna - Luleå.

Although the Dm2 the first two series were rebuilt in many details with members of the third Dm series, but always remained a little easier and the performance significantly weaker. The Dm3 the power was 6.210 kW in the pre-series and 7,200 kW in the third series. Prominent part in the rebuilding were the interesting SAB wheels with their rubber ring suspension of the tire.

With a total length of 35,250 mm, the locomotives were among the longest- electric locomotives in the world. However, they are still significantly exceeded in length and power of the successor series IORE, which are strictly speaking they are two independent and separately deployable locomotives.

The 14 heavy locomotives of the third series were considerably modernized in the 1990s and were doing a two -tone paint in blue, gray and red technical changes included the replacement of the mechanically operated tap changer by an electric drive switch, a Kriechgangsteuerung that when loading and unloading of the trains will be used, a sound insulation of the cabs as well as the installation of the driver's seat and cab on a sprung platform that are designed to keep the problems caused by the coupling rods vibrating movements of the engineer's. Before modernization, the locomotives had a brown color.

As of 2000, there were initially 15, then 13 locomotives in revenue service. Until 2013, all Dm3 were parked. The successor series IORE was sufficiently available and before the now of 5200 to 8160 (!) Tons of ore trains increased train weight is the Dm3 no longer be found.

Summary Table

All locomotives have received in the MTAB name after the LKAB mines, but also retain their original road number. Each locomotive part further has a unique number that has not changed during the conversion from double to Dreifachloks why the number of the middle part partially bears no relation to the two "ends".

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