this post was submitted on 17 Sep 2023
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Imagine if we somehow could run trains on electricity, that would be even better
They already do, they just have a diesel generator to make the electricity
Guessing that replacing that with a large battery that charges at night is unreasonable due to the torque needed? You'd probably need a battery larger than a train engine to be able to even do a few stops and starts. Which is why electric trains are wired all the time.
If someone knows for sure I'm super curious!
Is this whole thread a joke or have you people not heard of electrified rail
I mentioned it in my comment that you're replying to. "wired" could easily refer to above or below, just continuous current is what matters for this discussion. Why do ask?
Edit: Wait did you think we can electrify all rails? Outside of major cities it's a maintenance and safety nightmare, and a LOT of our freight moves via rail.
Global warming is a major maintenance and safety nightmare outside and inside major cities.
There are trains available that will run on overhead lines where available, and diesel when they're not. There's also passenger trains that have batteries as well.
It's doable, especially considering how efficient trains are.
It's kinda the default actually. Locomotives might lack pantographs if they never see electrified track but diesel locomotives aren't direct drive but diesel-electric. I'm not that deep into the topic but from what I've heard a mechanical transmission would be a nightmare.
Modern trains are almost exclusively electric final drive, off the top of my head I can't think of any exceptions. There are so many different voltages of overhead pantographs and drive motors though, there is almost always some type of converter needed to provide the right voltage to the drive motors.
Overhead wires aren't 3-phase, so convertor is required anyway.
A lot of locomotion uses DC motors, so they can run line voltage directly.
And what operational voltage of such motor?
1.5KV DC is reasonably common for commuter rail.
1.5KV doesn't sound like operating voltage of DC motor. Maybe you wanted to say BLDC instead?
You can electrify your rail because that's what we did.
No. Also outside of city cost of electrification is much cheaper.
Same for me
Not sure where you're from but if you pretend it's Switzerland then this comment is for you https://reddit.com/r/trains/s/UE3DSOPUdf
Not Switzerland, Russia
The problem with battery trains is that locomotives hardly sit around long enough to charge unless it's some sort of switcher or in for maintenance. Really the only use case for battery locomotives outside of switchers is passenger service where it's fairly common for a train to sit for eight plus hours. Amtrak and Siemens are actually doing this with 15 of the new airo trainsets which will run on the empire line. The trainsets will specifically run on battery while within the new York city tunnels where diesel locomotives are only allowed to operate under emergency.
There is probably a use for train with battery on partially electrified lines.
The train charge on the electrified part and use batteries on the rest.
https://www.mobility.siemens.com/global/en/portfolio/rail/rolling-stock/commuter-and-regional-trains/alternative-drives.html
It's definitely a thing already.
Trains are already pulling what 100 cars. It's easy enough to have a car that's a battery. But I think overhead lines are the way to go on the vast majority of lines.
Supercapacitors.
If I ran the local power grid I'm not sure I'd want cargo trains using line power for traction, unless there was some mandated weight or length limit 🤔
Without some cargo limit I think sections of the line's voltage will just collapse under the current being drawn, whenever the cargo train moves off from a complete stop - especially if it's a multi mile long cargo train that seems common in the US
The Kiruna - Narvik electrified line is operating just fine with LKAB running the heaviest trains in Europe with a mass of 8600 tonnes.
There's little chance of that happening, but even if there was, they'd just use batteries for the acceleration phase. That's what hydrogen fuel cell trains do anyway, because the fuel cell can't produce enough power on it's own to accelerate the train from a stop, so they're used to charge batteries that allow it to do so.
The reason why there's little chance of that happening is there are already very many cargo trains powered by overhead lines. We've been doing it for 150 years and in continental Europe there are many sections of track that are entirely electrified because it made more economic sense than running a wasteful (compared to a steam power plant) diesel generator to power the already electric engines of the trains.
90% off the cargo trains are powered with electricity in France and can reach up to 750m.
I agree It's not multi mile long but it's totally possible to have electric cargo trains.
I really can't see a train pulling so much that it crashes the entire system. *When you think about it it's one (moderate size) generators worth.
I think this guy never learned about resistance. Maybe he skipped physics classes, maybe he didn't even have them yet.
Would you ellaborate on what you mean, and the assumptions you drew from the quoted text?
Even better, we could also put cables above the train and connect them to an even bigger diesel generator located somewhere close to the railway. That would make the locomotive lighter and the energy production more efficient. Better yet, replace the diesel with uranium and you can easily power many trains.
That's not an advantage. You want your loco to be as heavy as possible for traction. If they were switching it to pantograph and it was lighter they'd add iron, or something else to make up the difference
I see you don't know why Caucasus was electrified. Non-electric locomotives were just too heavy and couldn't lift as much as mass as electric could.
I don't know about Poland but I know about France (I would guess we're not so far appart on this point).
While 95% of railways are electrified, those last 5% are not very worth it to invest in, because really low traffic and hard to operate (eg. in mountains). I've already heard of compromises, like hybrid locomotives that can run on battery for more than half the line and rely on diesel for the remaining.
In Soviet Union Caucasus was electrified first for this exact reason. Without electrification it was too hard to operate.
all trains, even the speed trains, in france run on electricity for who knows how many decades.
same trains go to great Britain, Belgium, Netherlands, Germany and maybe some other countries too.
source of the electricity is debatable though. France produces a great majority of its electricity from nuclear since the ww2 trauma.
Oh you mean debatable because it's one of the cleanest, cheapest, and safest sources of electricity we have?
Which allows France a degree of energy independence which has helped it not suffer the same amount of pain other countries have now that they're having to kick the cheap Russian gas addiction?
And through huge cross-border interconnects it allows France to sell electricity to neighbouring countries at a huge profit?
Nuclear is not always the answer, but as France has shown, as long as you invest in reliable infrastructure and don't put it in earthquake/tsunami-prone areas, it can be a huge positive for your country.
And you don't have to rely on antagonistic petrostates for to power your homes with gas, or on strip-mining huge swathes of land by equally-antagonistic China for rare-earth metals for your wind turbines/solar panels/battery storage.
by "debatable", i mean that the moment you mention it, debate starts. You proved me right and i thank you 😉
i think controversial fits it better
if you say so
Not trying to start a fight or anything, but don’t we still ‘need’ to burn a lot of coal to fuel electricity? Renewables haven’t gotten close to pushing the necessity of coal away yet, no? Why not alternatives like this in some places to offset the need for electricity?
Hydrogen doesn't exist randomly in a well or something it has to be created by using electricity - and that transformation is very inefficient if you then use the hydrogen in an inefficient way to power an engine instead of just using the electricity directly
That argument that energy is coal-heavy actually counts against hydrogen...
Hydrogen powered stuff only makes sense when electric isn't an option like for planes that just can't carry heavy batteries
Apparently, some hydrogen does come out of the ground like methane: https://www.weforum.org/agenda/2023/09/white-hydrogen-deposit-france/ but I assume it's not abundant enough to make a difference
You don't have to use electricity to make hydrogen! You can make it from methane! But yeah, it's probably even worse than a diesel engine when it comes to CO2 emissions...
While it technically doesn't you "need" electricity, Methane Pyrolysis requires energy of some sort.
The issue to me in term of effeciency is that the production of hydrogen needs electricity, the movement of it needs electricity, the storage and pumping of it needs electricity, and so on. I'd rather see all that electricity in the process simply be moving the vehicle. Though lugging batteries along is an issue in it's own.
What about wire?
What about it?
Nuclear is the energy source that scares everyone but that is actually the most viable option to power the world until renewable becomes the dominant one.
Thorium has been the best solution all along but it can't be weaponized so countries have been ignoring it for decades until recently
https://m.youtube.com/watch?v=EhAemz1v7dQ