9 ms·

https://en.wikipedia.org/wiki/Regenerative_braking#History https://en.wikipedia.org/wiki/Regenerative_braking#History Regenerative braking has been in extensiv

https://en.wikipedia.org/wiki/Regenerative_braking#History https://en.wikipedia.org/wiki/Regenerative_braking#History Regenerative braking has been in extensive use on railways for many decades. The Baku-Tbilisi-Batumi railway (Transcaucasus Railway or Georgian railway) started utilizing regenerative braking in the early 1930s. This was especially effective on the steep and dangerous Surami Pass. In Scandinavia the Kiruna to Narvik electrified railway, known as Malmbanan on the Swedish side and Ofoten Line on the Norwegian, carries iron ore on the steeply-graded route from the mines in Kiruna, in the north of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on the way down to Narvik, and these trains generate large amounts of electricity by regenerative braking, with a maximum recuperative braking force of 750 kN. From Riksgränsen on the national border to the Port of Narvik, the trains use only a fifth of the power they regenerate. The regenerated energy is sufficient to power the empty trains back up to the national border. Any excess energy from the railway is pumped into the power grid to supply homes and businesses in the region, and the railway is a net generator of electricity.

perilunar 3y ago
What's particularly interesting here is that the Pilbara, where the mines and trains in the article are located, is only 500–1000 metres elevation, and the train tracks are hundreds of kilometres long. So we are talking of an average grade of one in several hundred. i.e. very much not steep! Topographic map of the Pilbara: https://en.wikipedia.org/wiki/Pilbara#General https://en.wikipedia.org/wiki/Pilbara#General Map of the rail network: https://en.wikipedia.org/wiki/Railways_in_the_Pilbara https://en.wikipedia.org/wiki/Railways_in_the_Pilbara
- defrost 3y ago
  Also worth mentioning that Pilbara ore trains are consistently almost the longest trains in the world, (although just for fun BHP railways holds a record of operating the longest train in the word at 7.3km 99k tonnes in 2001). But they are likely the heaviest at around 42,000-43,000 tonnes per train with an average length at just under 3000 metres (1.85 miles) each. That's a lot of mass to drive recharging, and the laden to unladen ratio easily exceeds that of a European swallow. https://www.youtube.com/watch?v=vBXZbn7q7jQ https://www.youtube.com/watch?v=vBXZbn7q7jQ
  - perilunar 3y ago
    Yeah, there's probably a nice formula with peak and average grades, ratio of laden to unladen weight, rolling friction, and drive and recharge efficiencies, to determine whether it's possible or not.
    - defrost 3y ago
      Oddly enough I made such tables ~ 1985 as a side project to some mine event recording for optimising operation software I wrote as a side project to doing a degree.

perilunar 3y ago

What's particularly interesting here is that the Pilbara, where the mines and trains in the article are located, is only 500–1000 metres elevation, and the train tracks are hundreds of kilometres long. So we are talking of an average grade of one in several hundred. i.e. very much not steep! Topographic map of the Pilbara: https://en.wikipedia.org/wiki/Pilbara#General https://en.wikipedia.org/wiki/Pilbara#General Map of the rail network: https://en.wikipedia.org/wiki/Railways_in_the_Pilbara https://en.wikipedia.org/wiki/Railways_in_the_Pilbara

defrost 3y ago
Also worth mentioning that Pilbara ore trains are consistently almost the longest trains in the world, (although just for fun BHP railways holds a record of operating the longest train in the word at 7.3km 99k tonnes in 2001). But they are likely the heaviest at around 42,000-43,000 tonnes per train with an average length at just under 3000 metres (1.85 miles) each. That's a lot of mass to drive recharging, and the laden to unladen ratio easily exceeds that of a European swallow. https://www.youtube.com/watch?v=vBXZbn7q7jQ https://www.youtube.com/watch?v=vBXZbn7q7jQ
- perilunar 3y ago
  Yeah, there's probably a nice formula with peak and average grades, ratio of laden to unladen weight, rolling friction, and drive and recharge efficiencies, to determine whether it's possible or not.
  - defrost 3y ago
    Oddly enough I made such tables ~ 1985 as a side project to some mine event recording for optimising operation software I wrote as a side project to doing a degree.