Why are maglev trains still rare?

frightful_hobgoblin@lemmy.ml to Asklemmy@lemmy.ml – 237 points –

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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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.

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.

I would suspect it would be complex to design mag-lev for all the various types of loads trains for be subject to. Wheels are fairly versatile and have a wide range of loads.

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.

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.

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

There are some concepts for hybrid maglev-rail tracks that would at least solve the first point, similar to how rail was electrified over time. It would still be very expensive though.

Recent demonstration https://www.youtube.com/watch?v=CQOEP7_euXQ

woah this is awesome!

maglevs need classical wheel systems anyway because there might be a power outage, so simply having wheels that are compatible with the local rail system is a brilliant idea.

add in a tiny propulsion system so they can use the normal tracks at low speed without the help of the maglev tracks and you can sort of blend the two systems together in critical locations like switches and train stations.

  • 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.

What is grade-separate

They can't cross any other tracks/roads. I.e. everything else must go above/below it.

On one side, it can mean this. And for lighter railway construction, such as trams, light rail and rural regional trains, this can be optional. Plus it makes yards and depots easier to build, just slap a few concrete plates for a few crossings and the staff will find their way around. This is not possible with some maglev technologies

On another, it can also mean that the infrastructure is built directly on the ground. Being able to do so is extremely useful, since you don't need to build (as many) bridges or tunnels to have rail going somewhere. Again, for some maglev technologies, this is not an option.

A lot of these arguments apply to high speed train. In France a completely separate line was build between Paris and Marseille for the TGV To reach its peak speed without being delayed by lines that stop at every station.

The problem is investment and shitty companies holding these technologies IMO.

To compare our bullet points for maglev and high speed & conventional rail:

  • there's a big step in price between "a railway line built to millimetre precision" and "a completely new type of infrastructure that may or may not need superconductors to work"
  • there are way more manufacturers for components of high speed rail. For rolling stock there 4 in Europe alone, plus more in Japan, South Korea and China. As for signalling, it depends on the underlying tech. And if we follow the current European tech standard, that encompasses a standard... That is made by multiple manufacturers, and where their systems are operationally compatible.
  • for one, high speed rail is still rail, so building at grade & laying them on the ground is trivial compared to maglev systems. While some maglev technologies must be built like a bit of a monorail, which must be built elevated everywhere. And if we step outside of high speed rail, and point to rail in general, the mere existence of level crossings and street running disproves the fact it can only be built grade-separate. Sure, level crossings for HSR are a reason for the planning engineer to get fired, but for rail in general, it can happen.
  • this depends on what is already there. Most high speed trains use standard gauge, and those that don't, use broad gauge, and for that, only the Russian Sapsan comes to mind. If your country has standard gauge track, you can use the existing railway lines into town, disproving your point. And as for signalling, you can fit a train with multiple train protection systems, and many places are instead working towards using high speed signalling for general use, since the tech that makes high speed trains go BRR is the same tech that allows regular trains to run closer together. Finally, electrically, many countries use the same power on the wires on their high speed network as their general network.
  • I've seen footage of a set of switch points with a diverging speed of 160 km/h, and it needs 9 switch motors to work. Proper high speed switches need even more, last time I checked the adopted standard was diverging speeds of 220 km/h. However, these motors all work in parallel, so the difference in switching time is negligible compared to a more basic type for general use. And these points work by bending one rail a little bit out of the way, bending another rail into place, and for high speed, pushing the frog (image for clarity) to the other side. This all unlike maglev, where you need to invasively rearrange the whole track, the replacement of which is probably several metres away.

High speed rail has enough compatibilities with regular rail to make sense.

To append, some examples of high speed systems with multiple manufacturers.

🇪🇺🇬🇧: Eurostar has, for the Channel Tunnel, two types of train built by two manufacturers. The old type by Alstom, the new type by Siemens.

🇪🇸: Just AVE has three different builders. The S-101 by Alstom, the S-102 by Talgo and the S-103 by Siemens. The S-102 is also used by Avlo, while OuiGo used Euroduplex sets by Alstom, and Iryo uses ETR 1000 sets built by Hitachi Italy.

🇮🇹: The ETR 500 is built by a consortium of manufacturers, several of which have been absorbed by others. The ETR 1000 has been built by a chain of builders due to mergers n stuff. And the NTV units are built by Alstom.

🇯🇵: Pretty much every major manufacturer of rolling stock has built at least some Shinkansen units. You'll find trains by Hitachi, Mitsubishi, Kawasaki and others all over the network.

🇨🇳: The first generations of CHSR trains were all imported designs, derived from others, both Shinkansen and European types. This allowed them to kickstart a domestic rolling stock industry for later generations of train.

🇨🇭: Once we lower our standards of speed a touch, SBB uses two types, one by Alstom built in Italy, one by Stadler built domestically. And trains from neighbouring networks ride into particular areas, each of which has their own builders.

Maybe the new Japanese maglev Chuo Shinkansen will help - they've already had Mitsubishi, Nippon Sharyo (JR) and Hitachi build test trains for them

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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.

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.

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.

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

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.

Is that factoring in the always on cooling of the magnets?

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)

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.

Maglev's top speed record is just 5% faster than conventional train speed record. Thus if Maglev is more than 5% more expensive, then it doesn't make any sense to build them.

Speed records aren't usually representative of regular use top speeds, are they?

Well, if we look at actual maglev deployments in the real world, then they are much slower than conventional trains. All of them top out at 160kph, while conventional trains going below 200kph don't even count as high speed. There's only one Maglev line in the world which actually goes fast. So if we want to talk about regular speed representation, maglevs are slow and useless.

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.

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.

Brits are opposing HS2 simply because they are NIMBYies and oppose everything.

Not entirely accurate. There's a lot of support for HS2 in the North as it would greatly improve the infrastructure - but it's increasingly obvious that HS2 will only be built out as far as is politically beneficial for the government so the project will deliver high speed rail in the south then be abandoned due to massive costs.

South England will reap the benefits (again) paid for by the tax money of all.

I'm not sure that it is really paid "by all". London brings in 25% of all UK taxes while having only 13% of the population. Londoners are paying twice as much as everyone else and yet everyone else complains about "South England/London reaping the benefits". Maybe try to fund something without our help for once? Or at least say thanks.

You're welcome for all the commuters that need to be able to get in to London via our abysmal infrastructure to maintain its prominent position.

That's because HS2 is a totally flawed, Ill thought out, over budget and badly managed boondoggle - just like everything in the UK rail system since the Beeching cuts in the 60's. If it was properly run, well thought out - and actually made a significant difference in time (not approximately 15 minutes from Piccadilly to Euston), we'd support it.

I agree with all of that, but the thing is that faster journey times shouldn't be the main selling point of HS2 in the first place; it'll relieve capacity of the groaningly overused West Coast Mainline, allowing more freight and cheaper short journeys.

If it's properly managed.

Which it won't be.

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

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.

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.

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.

Also for the US the automotive and oil industries have powerful lobbies and an obvious interest in preventing the proliferation of electric-powered public transport. They’ve spent decades centering personal automobiles as the default method of travel and attack these projects with enthusiasm.

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.

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

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.

The ones in the train need to be super cooled or something

maglevs arent using fuckin superconducters to levitate, it's basic magnetic repulsion. Get whatever fictional version you've got in your head cleared up.

Both of you guys are correct, because there are two types of maglev trains; the Japanese tech (Shinkansen) and the German design (trans rapid).

I didn't even know Germany designed maglev train tech, usually when these trains are mentioned it's related to Japan or China. Interesting

The Germans built a maglev test track over 20 years ago

The Chinese maglev IS the German Transrapid. The Chinese don’t have the mental horsepower too design this kind of stuff

Bit savage but your phrasing just cracked me properly up in public

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.

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

What happened with that by the way? I'm assuming since I haven't seen huge headlines since, it's not been replicated or it's been proven to be a hoax

It was basically proven not to be a super conductor

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.

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

It's very sad tbh if it's the reason. It means the companies are unable to teach their knowledge, expand their market and attract investment by themselves despite clear advantages. I wouldn't be surprised, but it's still sad imo.

The core technologies that UTDC (then Bombardier, now Alstom) took from this is still being used all over the world. The new Vancouver SkyTrain is still using Linear Induction Motors.

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

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.

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

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.

You do save money on them in the long-run. I just assume it takes decades to get all that return on investment back out, thus any entity interested mainly in quarterly profits has little incentive to make the investment, which would be disruptive to their finances in the near-term.

Is that assuming there will not be major repairs?

Fewer major repairs is the way they save you money. Fewer moving parts, less friction, less wear and tear. All the energy savings gets tossed out the window in the interest of going faster, in the ones we've made so far anyway.

There may be fewer moving parts but that does not necessarily mean cheaper/less repairs. Current railway parts (especially wheels) are fairly low tech and easily fixed. What if the cooling of a superconducting magnet fails? That’s expensive.

Sure, I didn't say they never require maintenance or anything. Simply that over a long period of time they become cheaper to operate, after taking into account repair and replacement costs.

If you don't take repair and replacement costs into account, they become more expensive. This is probably another reason there are not many of them. Repair is where they save you the money though, due to how infrequently they require it.

If we somehow remove the friction of air on train body. Then maglev would be zero friction transport.

Edit : Oh my. My little joke comment has ballooned into a full on debate. And I'm not even aware of any of these things they're all saying.

I just made a comment guys, I'm not serious or not in any agenda.

Atmospheric Railway and Hyperloop bullshit all over again. Unless you're in space, this isn't feasible.

Its already been done

Sure on a small test track. As soon as it was meant to be scaled up, every attempt has been whittled down. Either it fails completely (Look up Brunel's Atmospheric Railway) or has been so expensive and impractical that it gets reduced to cars in tunnels.

If you are most concerned with efficiency, then building the cheaper HSR infrastructure to get freight off of roads and passengers off of planes as fast as possible should be the first priority. Holding even a partial vacuum in tubes hundreds of miles long just to eke out a little more energy efficiency is laughable. Everything leaks. Maintaining cabin pressure in a 73-meter plane is a completely different beast from maintaining vacuum in miles of tube. It's likely that maintaining the tubes will end up costing so much that any efficiency gains acquired from the vacuum will evaporate.

The vegas loop is its own dumb thing, its not relevant.

For the leak thing, dont just assume whatever wild claim that benefits your side. Heres a DoE study, if you search leak youll find an estimated power usage profile, with large spikes for acceleration, and a sliver of an orange bar across the profile as the baseline load for maintaining vacuum against leaks https://www.energy.gov/eere/vehicles/articles/effect-hyperloop-technologies-electric-grid-and-transportation-energy

When I'm talking about leaks, I'm not talking about the extra energy required to constantly run vacuum pumps. I'm saying that HSR infrastructure needs inspection and occasional repair, but not nearly to the extent that a vacuum tube based solution would. Any savings made via efficiency are pissed away by having to pay more maintenance crews and material cost to maintain the infrastructure. The tubes are also much less likely to be able to be automatically inspected like rails can be using inspection cars because any train moving through the tube can only inspect the interior walls. Besides, rail already exists across much of the US for use as freight infrastructure. These same rails, if inspected and tested properly, can be used for high speed rail much more immediately than waiting for tubes to be built. Besides all of this, more aerodynamic trains can and have been built, but are not in use in the US. Instead, we send bricks down the rails. The "immense" efficiency gain from 0.5 atmospheres of air pressure is likely significantly less impressive when compared against well designed trains with regards to aerodynamics.

All of this is also completely ignoring how dangerous tunnels are for fires. Even with proper safety precautions, fires in tunnels are exceptionally dangerous. By venting out the smoke that kills people, you increase the intensity of the fire that also kills people.

Oh man yeah welded joints are just falling apart every week, it takes a fortune to upkeep some stationary metal.

I dont think you understand air's role in aerodynamics. At half atmosphere...you've plainly removed half the friction, there is half the air molecules to collide with the train. To give some perspective, all of the fastest manmade vehicles, by crazy high magnitudes of difference, are space vehicles. The ISS is whizzing around at nearly 5 miles a second in low earth orbit. Air is the limiting factor in speed. Its the only reason any additional fuel needs burning to maintain speed.

Finally...youre not gonna have a fire in a vacuum tube

if only this was a proposed technology

You mean that hyper idiotic Hyperloop idea that’s just a warmed up remix of the vacuum train idea from the 1920s and will efficiently kill all passengers if a little thing goes wrong (if you can get a hundreds of kilometres long vacuum chamber airtight anyway)?

its a big topic, just be aware that "vacuum" in the real world is a sliding scale of air pressure. vacuum tube doesnt automatically mean conditions on a spacecraft in sci-fi when a hole is shot through a window. You can cut air pressure to half of atmospheric, and have an extremely weak vacuum, and still get amazing efficiency gains. We already have routine transit of pressurized cabins in the form of planes.

Still means 0.5 bar overpressure if something breaks, which is deadly. Also the proposed pressure for the Hyperloop was 0.1 atmospheres iirc. If there is a weakness in the tube it will fail catastrophically and a pressure wave kills anyone in it. Watch the video where the mythbusters implode that huge tank.

You basically bring a lot of the problems with space travel down to earth.

"vacuum tube doesnt automatically mean conditions on a spacecraft in sci-fi "

Half atmosphere is less pressure difference than normal passenger planes.

The direction of pressure difference is important

Its the same? Pressurized cabin in a lower pressure environment

The problem is the high pressure environment outside the low pressure environment

They're quite expensive for a start and standard HSR does it's job just fine.

Japan is the only country that's building actual Maglev lines. It's feasible in Japan due to popularity of rail and distance between the endpoints makes it worth it.

China has Maglev tech and also some demo Maglev lines. But they are committed to standard rail because it's cheaper to build using a standardised process and works good enough on large distance travel required in China.

In the US, it's nearly impossible because Petroleum companies and such hate the idea of cheap and efficient transport and just bribe the politicians to be against it.

I rode the maglev to the shanghai airport, it was awesome. The newer version in Beijing is significantly faster. But yeah super expensive to build.

How was the ride? Smooth/bumpy/not feel much movement?

My experience on a much slower HSR is being thrown around in the seat at certain times, wouldn't want to be carrying an open drink of any kind tbh lol

The maglev is Shanghai is super smooth.

TGV in France is super smooth. Maybe not quite as smooth but still smooth enough that you can have a tall bottle or glass on a table without fear it’ll fall over.

Then you’ve got a couple of places in Europe that hits 300 km/h, or near enough: Köln-Frankfurt and parts of the München-Berlin in Germany, Barcelona-Madrid and the Eurostar. All of these are super smooth.

The rest is just “high speed” marketing, sometimes done on tilting trains that’ll hit 250 km/h. The ones I’ve tried are not super smooth. Parts of the “higher speed” tilting trains in the U.K. are downright uncomfortable and can leave you travel sick at times.

because cars cars cars

This argument may be true in regards to rail in general. This specific question is “why not maglev instead of rail”. That’s not car’s fault - it’s just extremely expensive to build maglev and that’s compared even to regular high speed trains.