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submitted 9 months ago by [email protected] to c/[email protected]

They were invented decades ago.

They have fewer moving parts than wheelbois.

They require less maintenance.

There's obviously some bottleneck in expanding maglev technology, but what is it?

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[-] [email protected] 127 points 9 months ago

If you introduce a new rail type into your rail network you can't use your existing fleet of trains on that section reducing the ROI on that train engine or carriage. Also, any train you purchase for the new rail type will only ever work on that system lowering their profitability in the long term.

[-] [email protected] 43 points 9 months ago

A million times this. Mag-lev only works for either super dense routes where the added cost as you describe can be displaced by the immense value add of shorter and generally more comfortable travel. Or in nations that can force through decisions from the top down, such that cost becomes almost a non-factor like China. Rail in general across the western world is a weird mix of nationalized and privately owned companies and operators, such that introducing mag-lev with the intent to replace conventional rail would require compensation to the private companies who have invested billions in the current infrastructure else they simply won't be part of the new one, with all the issues that entail.

From an environmental standpoint it's also really hard to see an ROI in scrapping something that works in favor of mining, constructing and spending intense amounts of energy in all forms to build something better but only moderately so. The biggest improvement is moving from trucks to (electric) train for freight, going from electric train to mag-lev is only slightly better so the ROI just won't be there.

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[-] [email protected] 27 points 9 months ago* (last edited 9 months ago)

Also the fact that 'less moving parts' doesn't mean lower complexity or maintenance cost. Train wheels are a very robust and efficienct mechanism and most train designs are not being limited by them.

[-] [email protected] 6 points 9 months ago

Very robust because they have 300 years of research, innovation, materials science and manufacturing in them. Making them incredibly stellar, well understood, damn near perfect technology for what they do.

[-] [email protected] 9 points 9 months ago

Also them just being wheels in general which are one of the most efficient and simple ways to move stuff.

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[-] [email protected] 59 points 9 months ago

Because it's not currently profitable in most cases. Capitalism ensures that the merit of an idea comes secondary to it's profitability. We don't get the best things, we get the profitable things.

[-] [email protected] 26 points 9 months ago

Not to defend capitalism in general, but it’s really good at answering these sort of “is it worth the cost?” aquestions. The whole point is to allocate scarce resources efficiently; the problem is that it assumes nobody is a scumbag and all the costs are accounted for.

[-] [email protected] 6 points 9 months ago

That's really just markets, though. You can have markets with different methods of economic organization.

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[-] [email protected] 9 points 9 months ago

What kind of benefits are there to maglev trains that are not cost related?

[-] [email protected] 9 points 9 months ago

They're faster and more comfortable than traditional rail. They could help to reduce air and vehicle travel

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[-] [email protected] 6 points 9 months ago

"MVP" stands for "minimum viable product".

[-] [email protected] 6 points 9 months ago

Where are all the maglev trains in non-capitalist countries? Sooner or later, in any system, someone has to do a cost benefit analysis and decide whether it's worth it. It's not just about profitability. There are plenty of situations in the US where something is unprofitable but still funded because the benefit is worth it.

[-] [email protected] 13 points 9 months ago

Dude, without capitalism we’d be living in flying maglev RVs on mars with free robot labour bro

[-] [email protected] 8 points 9 months ago

Three of the six currently operating maglevs are in communist china

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[-] [email protected] 50 points 9 months ago

The same reason supersonic passenger jets are rare.

The extra speed comes with a massive increase in costs.

Travel 30% faster than high speed rail for 10-20 times the cost.

[-] [email protected] 12 points 9 months ago

Is the claim about "10-20 times the cost" true? The internet says Shanghai maglev cost $1.33 billion for 30.5 km, i.e. less than $44 million/km. Compare https://transitcosts.com/new-data/ or https://transitcosts.com/high-speed-rail-preliminary-data-analysis/

Secondly, if it is true, why would it be true? Why would it be more expensive to build something with fewer moving parts?

Supersonic passeenger jets require more energy. Maglev trains require less energy.

[-] [email protected] 21 points 9 months ago

all the other complex and important factors aside, air restistance is a formula of speed squared. Meaning for example if you bump speed up by 40% you double air resistance, and therefore double the energy cost of transport.

[-] [email protected] 12 points 9 months ago

Isn’t that only applicable for identical trains? For sake argument, if you had two identical trains designed with poor aerodynamics, one at 100mph and one at 140mph then you can double the energy cost. But if you take two different trains with one designed to be more aerodynamic, at the same speed they wouldn’t have the same energy cost as the second has a better profile?

Plus theres less friction from needing to be on a rail.

So I think saying its double the cost of transport is too simplistic to be meaningful in this discussion

[-] [email protected] 8 points 9 months ago

It's more than that - doubling air resistance only doubles the energy use if it's the only inefficiency on the train (e.g., no losses in the magnets, HVAC, lighting, etc.). Add onto that the fact that you're basically eliminating rolling resistance from traditional trains when switching to maglev, and the expected outcome should be much less than double.

Finally, the most important part, each high speed rail route of any meaningful distance has the opportunity to displace a certain amount of air travel, so big picture, HSR results in a significant decrease in overall energy consumption.

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[-] [email protected] 16 points 9 months ago

Maglev requires superconductors to work. They must be cooled to just a few degrees above absolute zero (typically ~ -270 celsius) and if they ever warm up beyond their critical temperature, catastrophic failure is the result. (this is called quenching which can destroy the superconductor permanently) So not only can you only drive maglev trains (which are expensive themselves) on maglev track and can only drive mag lev trains on maglev track, its far more expensive to build and maintain superconducting infrastructure than it is to lay down some steel rails. Maglev trains are used because the only friction that they experience is from air resistance. Theyre much faster than normal trains but it takes a lot of energy to keep the superconductor that makes them work cool, costs a lot more to build and requires a lot of electricity to get them up to speed. (They can use regenerative braking to recover much of this but its still an energy intensive process)

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[-] [email protected] 6 points 9 months ago

Japan is in the late stages of developing a maglev section of the Shinkansen. It has liquid helium cooling for semiconductors and lots of considerations to make sure the cabin and surroundings aren't exposed to very strong magnetic fields. It's just more expensive to do all that.

After Japan rolls this out and works out the kinks, it might get cheaper since a lot of they've done a lot of the development.

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[-] [email protected] 42 points 9 months ago
  • construction is Hella pricey
  • there are few maglev manufacturers, allowing vendor locking and exacerbating the first point
  • they must be built grade-separate, which can complicate route planning
  • they are incompatible with existing rail tech, which results in having to build new, expensive infrastructure for 100% of your route, further exacerbating the first point
  • their switches are slow, limiting capacity

Ultimately, their competition is regular trains, which are simpler, more tolerant to buying from multiple manufacturers, still significantly more efficient and faster than anything roadborne, able to switch over the course of seconds instead of minutes, able to interoperate with different tiers of intensity and speed, able to be built at grade, cheaper and having the better part of two hundred years of technological refinement behind it. Ultimately, maglev has specific, niche advantages that make it a hard sell for any system that already has regular rail.

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[-] [email protected] 37 points 9 months ago

They're super expensive. Few people are willing to pay the massive amount extra for the slight dectease in travel time. Investors also know that.

[-] [email protected] 12 points 9 months ago

Look at HS2 in Britain and how people are against the cost for higher speed options, or California HSR. I'm all for it, it should absolutely be done, but getting taxpayers to see 10 years into the future is difficult.

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[-] [email protected] 32 points 9 months ago

Plane maglev tracks are way more expensive than wheeled train tracks. It's slower to get expensive when the terrain stops being plane, but it takes a lot of roughness for it to become cheaper. Most countries just do without trains crossing rough terrain.

And the largest cost of almost any train is the tracks.

[-] [email protected] 23 points 9 months ago* (last edited 9 months ago)

What is a Maglev train? (From WIki)

Maglev (derived from magnetic levitation) is a system of train transportation that uses two sets of electromagnets: one set to repel and push the train up off the track, and another set to move the elevated train ahead, taking advantage of the lack of friction. Such trains rise approximately 10 centimetres (4 in) off the track. There are both high-speed, intercity maglev systems (over 400 kilometres per hour or 250 miles per hour), and low-speed, urban maglev systems (80–200 kilometres per hour or 50–124 miles per hour) under development and being built.

Why so little?

Despite over a century of research and development, there are only six operational maglev trains today — three in China, two in South Korea, and one in Japan. Maglev can be hard to economically justify for certain locations, however it has notable benefits over conventional railway systems, which includes lower operating and maintenance costs (with zero rolling friction its parts do not wear out quickly and hence less need to replace parts often), significantly lower odds of derailment (due to its design), an extremely quiet and smooth ride for passengers, little to no air pollution, and the railcars can be built wider and make it more comfortable and spacious for passengers.

Cute link to the Wikipedia Page

I am a curious human, beep boop

[-] [email protected] 22 points 9 months ago* (last edited 9 months ago)

Where existing transit infrastructure exists, cities prefer upgrading existing infrastructure, rather than installing new infrastructure in its place, and where transit does not exist cities prefer not to install anything at all and favor cars typically. Maglev trains are extremely expensive to install the infrastructure, so gathering the money out of local budgets to invest in the extremely expensive maglev infrastructure is typically very difficult.

In the US in particular, politicians, just don’t look at the picture in the long term, and only focus on short term investigator as it pertains to their election schedule, and that is sad and has long-term impact on the local population.

[-] [email protected] 7 points 9 months ago

Think about it this way, OP: You know when they're working on the train network, how much you loathe commuting while a single line is out? How much of a pain replacement bus transportation is?

Now imagine having to do this for all train lines, everywhere, and you always have to switch trains (due to the difference in track) in between the blocks of replaced track. Plus you can't neatly fit maglev where conventional track fits and vice versa, plus you need the power infrastructure, plus you need to find a way to buy the rolling stock without already selling the old one.

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[-] [email protected] 20 points 9 months ago

I read it's the zoning and maintenance of the tracks. Since they probably have to be very precisely laid in order to support such a fast train.

That said I do wish for maglev trains to be accessible to all. I'd love to go across the states in a few hours on a train.

[-] [email protected] 8 points 9 months ago

Plus, any maglev project has to be a new build and not outright replace existing lines. Replacing a line would require closing and removing the existing line, extensive reconstruction of the track bed, and probably delays or closure to tracks sharing the line. It's not an easy thing for the government to justify when it would be cheaper and easier to simply improve the existing rail infrastructure. Or..you know...ignore the problem which is what they seem to be doing anyways

[-] [email protected] 16 points 9 months ago* (last edited 9 months ago)

You still need rubber wheels when it's stopped and at low speed. They retract when it's fast enough for the maglev to take over.

The electrical conductors are expensive as shit. The ones in the train need to be super cooled or something. The track ones need to be built along the entire length. On three sides, one vertically and two horizontally. Along with massive power lines along the whole length. They don't need to move to be expensive.

The right of way needs to be very straight. So compared to normal high speed, you have to spend much more on buying land, earth moving, tunneling, etc.

All this needs to be maintained to an extremely high degree because you can't accept a failure. The engine on a high speed rail fails and you just slow down, no biggie. HSR track is fairly robust and can easily be inspected visually. Since it has the same base as normal passenger and freight you have an entire industry knowledge and inspection machines. Any part of maglev fails and you have a catastrophic failure.

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[-] [email protected] 13 points 9 months ago

One other thing I've not seen mentioned yet is capacity. Switching a maglev track is difficult and very slow, which reduces the number of trains you can get through a switch and therefore the number of people your system can carry.

[-] [email protected] 11 points 9 months ago

Part of it, at least in California, is certain billionaire grifters derailing the effort to get high speed rail going at all and sucking up that subsidy money to do silly shit like LED-lit car tunnels.

https://www.reddit.com/r/fuckcars/comments/xhx6da/elon_musk_announced_hyperloop_to_kill_californias/

[-] [email protected] 9 points 9 months ago

We don't have yet room temperature Supra conductors, it's also why there was so much buzz about LK 99 this summer

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[-] [email protected] 7 points 9 months ago

It makes more economic sense to improve the rails we already have, and build faster trains to run on the existing rails (like the TGV), than building completely new infrastructure.

[-] [email protected] 7 points 9 months ago

Here's an interesting write-up about an attempt to develop a large-scale urban maglev system in the 1970s: https://en.wikipedia.org/wiki/Krauss-Maffei_Transurban

tl;dr: there were so many technical issues that when the West German company developing the tech lost funding and the Ontario government took over the project, they immediately abandoned the maglev concept and replaced it with linear-induction propulsion with steel wheels on rails (the mag, without the lev).

Even this tech, which does have a few advantages over conventional rail and is still used today in cities like Vancouver, is falling out of favour due to general logistical issues with using bespoke technology over conventional rail -- fewer people know how to build and maintain it, you're relying on usually just one company to supply your trains and infrastructure until the end of time, you can't reuse any existing infrastructure, etc. I'd imagine these issues still get in the way of maglev development today -- even more so because you can't even reuse existing rails

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[-] [email protected] 7 points 9 months ago* (last edited 9 months ago)

As others here have already mentioned the infrastructure costs alone are a huge problem, where I live we are currently just trying to electrify the corridor and it’s not even the entire system, once again the overall rail infrastructure is already there (it’s just electrification) yet this is still going to take a minimum of a decade and the minimum cost is going to be more than $11bn, technically this saves money as you don’t need to buy a new fleet of rolling stock just upgrade the old ones.

So ya for a maglev you would need a completely different infrastructure and the rolling stock

[-] [email protected] 6 points 9 months ago

They're very expensive to build. That's it, really.

[-] [email protected] 9 points 9 months ago

If it had a significant advantage the expense would be worth it, but steel wheels on steel rails already have a coefficient of friction 10x lower than rubber tires on asphalt, so it's not worth it.

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[-] [email protected] 6 points 9 months ago

I remembered seeing a video by Real Engineering that explained a lot on Maglev and it's pros and cons but one of the summaries that really hit it off for me and if I remember correctly is that it cost 11 times more to build per kilometre compared to conventional high speed rail, for about 70% more top speed while using 30% more energy.

https://www.youtube.com/watch?v=S4L_0CDsd1I

Personally I feel unless they come up with better superconductors, there's still a long way to go before it really takes off.

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this post was submitted on 08 Sep 2023
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