4 ms·

Yes and no. I know nothing about Norway's rail system, but it was the case in the UK that a lot of electrified rail was only partially used because services tha

Yes and no. I know nothing about Norway's rail system, but it was the case in the UK that a lot of electrified rail was only partially used because services that ran on both electrified and non-electrified tracks needed to be powered by diesel for the entire journey. This has got a lot better more recently as we now have hybrid trains that can run on electricity whenever there are overhead lines, and diesel where there aren't. There is talk of replacing diesel engines with batteries so that they can run on electric (and use regenerative braking) even where there are no overhead lines, charging the batteries from the overhead line when available. https://anonw.com/2023/06/27/what-will-be-the-range-of-a-hitachi-class-800-battery-train/ https://anonw.com/2023/06/27/what-will-be-the-range-of-a-hit... There are usually multiple diesel generators on each train, so it's likely that the batteries will only replace some of them - there would still be some diesel power available for emergencies.

theluketaylor 3y ago
The most expensive part of electrifying existing track is bridges and tunnels since they often have to be rebuilt to have enough clearance (especially in places like the UK where bridges are old and therefore very low. If all the trains have enough battery to move a short distance without the overhead wires suddenly the electrification project becomes pretty simple and non-disruptive and costs are really reasonable.
- cjrp 3y ago
  Is the clearance needed even if they're powered by the third rail? Or only for overhead pickup
  - theluketaylor 3y ago
    Overhead only. But 3rd rail for long distances is really dangerous. Subways and metros use it since they typically strongly control access to the tracks and tunnels, but that really isn't possible when crossing whole countries.
    - wkat4242 3y ago
      Still, you could use third rail in tunnels which can be tightly controlled, and overhead elsewhere. Dual trains exist, many metros have it too.
      - rjmunro 3y ago
        In the UK, 3rd rail is typically 600V (DC), where as overhead is 25kV (AC). So you need 40× the current to get the same power. For high powered intercity trains that run at around 1MW of power, it increases transmission losses substantially.

theluketaylor 3y ago

The most expensive part of electrifying existing track is bridges and tunnels since they often have to be rebuilt to have enough clearance (especially in places like the UK where bridges are old and therefore very low. If all the trains have enough battery to move a short distance without the overhead wires suddenly the electrification project becomes pretty simple and non-disruptive and costs are really reasonable.

cjrp 3y ago
Is the clearance needed even if they're powered by the third rail? Or only for overhead pickup
- theluketaylor 3y ago
  Overhead only. But 3rd rail for long distances is really dangerous. Subways and metros use it since they typically strongly control access to the tracks and tunnels, but that really isn't possible when crossing whole countries.
  - wkat4242 3y ago
    Still, you could use third rail in tunnels which can be tightly controlled, and overhead elsewhere. Dual trains exist, many metros have it too.
    - rjmunro 3y ago
      In the UK, 3rd rail is typically 600V (DC), where as overhead is 25kV (AC). So you need 40× the current to get the same power. For high powered intercity trains that run at around 1MW of power, it increases transmission losses substantially.