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Battery trains aren't a new thing. Prussia had been using them since 1907 and German federal rail later used the newer Class 515 [1] for decades. They had a rea

Battery trains aren't a new thing. Prussia had been using them since 1907 and German federal rail later used the newer Class 515 [1] for decades. They had a reach of about 300 km (theoretically and in level areas). For the 515, costs were a big factor. The lead based batteries had to be rented from the manufacturer. But even if you take current technology into account: A train isn't a Tesla. It needs much more energy to accelerate. Currently, an engine and a diesel tank are much cheaper to buy and especially maintain. They will give you decades of use. How long are your batteries going to last? Also keep in mind that batteries add tremendous weight, reducing reach again. More weight is especially painful in hilly areas. All of this needs to be factored in. Bottom line: It's feasible and has been done. Operating costs, however, are a big factor, especially compared to what other technologies get you. edit: There's a battery version of the Stadler FLIRT [2]. It went 224 km (at about 80 km/h) on one battery charge recently [3]. They will be in operation for DB from the end of 2022 on. [1] https://en.wikipedia.org/wiki/DB_Class_ETA_150 https://en.wikipedia.org/wiki/DB_Class_ETA_150 [2] https://en.wikipedia.org/wiki/Stadler_FLIRT https://en.wikipedia.org/wiki/Stadler_FLIRT [3] https://www.youtube.com/watch?v=m0Z7H3fv4Bc https://www.youtube.com/watch?v=m0Z7H3fv4Bc

loonster 4y ago
The big acceleration points are predictable. Electrify those areas. Then you only need enough batteries to maintain speed and get through the lesser acceleration points. They would still want enough batteries to accelerate from a dead stop to prevent a 5 minute delay from becoming a 5 hour delay. Energizing the acceleration points would be more about reducing wear on the batteries and prolonging their life.
- AnonymousPlanet 4y ago
  I don't think constantly raising and lowering the pantograph is a practical solution. Having lines with spotty overhead is very error prone and reliability is a big factor in rail. If we're talking about longer sections that are either electrified or not, things are different. E.g., extending the line for 100 km into an unelectrified part. Trains like the Stadler LINT (see my edit above), could make that happen.
  - Reason077 4y ago
    > "I don't think constantly raising and lowering the pantograph is a practical solution." I don't see why not. There are actually urban routes in London (London Overground) that do this multiple times on every journey! Switching between overhead AC electrification used in North London and the older third-rail DC electrification used in South London. > "Having lines with spotty overhead is very error prone and reliability is a big factor in rail. " But that's where batteries come in. Being able to keep moving under your own power if there's a problem with the overhead wires adds a lot of robustness/redundancy.
    - AnonymousPlanet 4y ago
      It depends on how long these sections are. We're probably of the same mind but thinking of different dimensions. If we're talking just for electrified sections of up to 2 km, alternating a dozen times or more, I'm not sure if it's worth it. For longer sections, yes, it's an absolute killer feature. The cost of raising the panto slightly too early even once is tremendous. You would have to close the track for maintenance. So you need a safety margin of a few seconds. That's several 100 meters. Frequent changeovers would necessitate the system to be fully automated in order to factor out human error. The changeover on London Overground is usually done while standing at a station (by the driver). According to [1] it's possible to switch while moving. The speed limit is given as 25mph, however. [1] https://www.railforums.co.uk/threads/changing-from-dc-to-ac-whilst-moving.60417/ https://www.railforums.co.uk/threads/changing-from-dc-to-ac-...
      - Reason077 4y ago
        Yes, you'd certainly make sure everything was automated or at least have a software lock-out to ensure the pantograph is only raised on the correct sections. But having a battery makes this a lot simpler, there'd be no need to stop or coast during the changeover.
    - LargoLasskhyfv 4y ago
      It's a special operation, requiring special signage, and awareness of the driver. Here in Hamburg, where the S-Bahn using third-rail got extended to service Stade, is using multi-system rolling stock now. Which traverses the gaps by rolling without power through that gap. I also remember standing on some platform above ground, where you could see them coming over a ramp, with the pantograph up, on a piece of track using third rail. Wondering how that happened, and what would happen if it goes back into a tunnel (with third rail), like that. Or under a bridge, overpass, all built with low clearance, because: hey, third rail! Nerd that I am, I walked up to the driver, knocking on the glass and asked: "Moin, do you know your pantgraph is up?" Turned out he didn't, and there wasn't any indication. He got it down by repeatedly switching up/down, and finally it stayed down. Two minutes late!1!! ;-)
Reason077 4y ago
> "Currently, an engine and a diesel tank are much cheaper to buy and especially maintain." Yes, diesel is cheaper to buy than battery trains. But pretty much everyone, including the main article here, agrees that maintenance costs are much lower with electric trains compared to diesel. I'd expect that (at least once the technology matures) this will also be true of battery electrics. The point is, if you start with the assumption that diesel is unacceptable and routes must be electrified - for reasons like climate change, toxic air pollution, route reliability, passenger comfort, etc, then there are many routes where battery electrics are going to greatly reduce costs compared to installing overhead wires on every section of track. > "There's a battery version of the Stadler FLIRT [2]. It went 224 km (at about 80 km/h) on one battery charge recently [3]. They will be in operation for DB from the end of 2022 on." Yes, I expect we'll see a lot more battery electric units introduced in Europe in the coming years. There are so many routes where they make perfect sense.
Reason077 4y ago
> "Battery trains aren't a new thing." Indeed, and neither are electric cars. But battery chemistry, electric motors and inverters, and controller software and hardware have all come a long way in that time. The technology is far more viable and efficient today than it was back then!

loonster 4y ago

The big acceleration points are predictable. Electrify those areas. Then you only need enough batteries to maintain speed and get through the lesser acceleration points. They would still want enough batteries to accelerate from a dead stop to prevent a 5 minute delay from becoming a 5 hour delay. Energizing the acceleration points would be more about reducing wear on the batteries and prolonging their life.

AnonymousPlanet 4y ago
I don't think constantly raising and lowering the pantograph is a practical solution. Having lines with spotty overhead is very error prone and reliability is a big factor in rail. If we're talking about longer sections that are either electrified or not, things are different. E.g., extending the line for 100 km into an unelectrified part. Trains like the Stadler LINT (see my edit above), could make that happen.
- Reason077 4y ago
  > "I don't think constantly raising and lowering the pantograph is a practical solution." I don't see why not. There are actually urban routes in London (London Overground) that do this multiple times on every journey! Switching between overhead AC electrification used in North London and the older third-rail DC electrification used in South London. > "Having lines with spotty overhead is very error prone and reliability is a big factor in rail. " But that's where batteries come in. Being able to keep moving under your own power if there's a problem with the overhead wires adds a lot of robustness/redundancy.
  - AnonymousPlanet 4y ago
    It depends on how long these sections are. We're probably of the same mind but thinking of different dimensions. If we're talking just for electrified sections of up to 2 km, alternating a dozen times or more, I'm not sure if it's worth it. For longer sections, yes, it's an absolute killer feature. The cost of raising the panto slightly too early even once is tremendous. You would have to close the track for maintenance. So you need a safety margin of a few seconds. That's several 100 meters. Frequent changeovers would necessitate the system to be fully automated in order to factor out human error. The changeover on London Overground is usually done while standing at a station (by the driver). According to [1] it's possible to switch while moving. The speed limit is given as 25mph, however. [1] https://www.railforums.co.uk/threads/changing-from-dc-to-ac-whilst-moving.60417/ https://www.railforums.co.uk/threads/changing-from-dc-to-ac-...
    - Reason077 4y ago
      Yes, you'd certainly make sure everything was automated or at least have a software lock-out to ensure the pantograph is only raised on the correct sections. But having a battery makes this a lot simpler, there'd be no need to stop or coast during the changeover.
  - LargoLasskhyfv 4y ago
    It's a special operation, requiring special signage, and awareness of the driver. Here in Hamburg, where the S-Bahn using third-rail got extended to service Stade, is using multi-system rolling stock now. Which traverses the gaps by rolling without power through that gap. I also remember standing on some platform above ground, where you could see them coming over a ramp, with the pantograph up, on a piece of track using third rail. Wondering how that happened, and what would happen if it goes back into a tunnel (with third rail), like that. Or under a bridge, overpass, all built with low clearance, because: hey, third rail! Nerd that I am, I walked up to the driver, knocking on the glass and asked: "Moin, do you know your pantgraph is up?" Turned out he didn't, and there wasn't any indication. He got it down by repeatedly switching up/down, and finally it stayed down. Two minutes late!1!! ;-)

Reason077 4y ago

> "Currently, an engine and a diesel tank are much cheaper to buy and especially maintain." Yes, diesel is cheaper to buy than battery trains. But pretty much everyone, including the main article here, agrees that maintenance costs are much lower with electric trains compared to diesel. I'd expect that (at least once the technology matures) this will also be true of battery electrics. The point is, if you start with the assumption that diesel is unacceptable and routes must be electrified - for reasons like climate change, toxic air pollution, route reliability, passenger comfort, etc, then there are many routes where battery electrics are going to greatly reduce costs compared to installing overhead wires on every section of track. > "There's a battery version of the Stadler FLIRT [2]. It went 224 km (at about 80 km/h) on one battery charge recently [3]. They will be in operation for DB from the end of 2022 on." Yes, I expect we'll see a lot more battery electric units introduced in Europe in the coming years. There are so many routes where they make perfect sense.

Reason077 4y ago

> "Battery trains aren't a new thing." Indeed, and neither are electric cars. But battery chemistry, electric motors and inverters, and controller software and hardware have all come a long way in that time. The technology is far more viable and efficient today than it was back then!