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By comrade1234 2026-03-0312:082 reply The Shanghai airport maglev used to go around that speed too (~430km/h) over twenty years ago. But these new trains are regular trains running on regular (but specialized and high quality) tracks. There's probably no more need for maglev now that you can run on regular (well not exactly) tracks.
Did it? I took a ride on the Shanghai airport maglev around a month ago, and it never went above 300 km/h, which was a real bummer, to be honest.
By CorrectHorseBat 2026-03-0312:37 I remember there were different speeds at different times last time I went, but it seems they reduced it in 2021 permanently.
By xenospn 2026-03-0319:55 I was there 20 years ago and it was ~500km/h, if I remember correctly.
By Cyuonut 2026-03-0313:44 Yes it did, at least earlier. I rode it in 2010.
By alexpotato 2026-03-0312:146 reply At these speeds, how are they guaranteeing that the tracks are in PERFECT working order?
e.g. even a small earthquake that shifts the tracks a few inches would probably cause, at minimum, a degradation in service.
By Animats 2026-03-0312:50 It does require really good maintenance-of-way work.
Having all trains inspect the track is feasible. The latest round of Shinkansen trains does that. They're moving away from running a Dr. Yellow track inspection train every 10 days.[1]
[1] https://www.railway.supply/n700s-trains-to-be-equipped-with-...
Japan has solved that 60+ years ago in a much more seismically active zone, it's not a major issue.
By SapporoChris 2026-03-0317:55 seismometers installed along the coast and near the tracks. Senses the earthquake and trains respond if necessary. I believe if the epicenter of the quake occurred directly under a moving train this system would fail(or too close react). However, that appears never to have happened and is probably extremely unlikely.
By api 2026-03-0312:44 Sensors all over the tracks? There’s probably many different sensor strategies you could use to detect imperfections.
I know that modern roller coasters are outfitted with a bunch of stress, vibration, conductivity, etc sensors. There’s a theme park near me where huge fast roller coasters run all day every day all season. The speeds aren’t as high but I bet given the twists and turns the stresses and tolerances are worse.
By thenthenthen 2026-03-0312:251 reply There are high fps cameras that monitor the overhead lines on every carriage, maybe also pointing at the rails? It is a engineering marvel though, the rides are so smooth, in my home country the trains have issues with leafs on the tracks … lol
By pixl97 2026-03-0319:04 This sounds like a Plainly Difficult moment.
By arethuza 2026-03-0312:32 I suspect ~200 years ago in England people were saying pretty similar things!
By expedition32 2026-03-0315:19 In my country there are special trains equiped with sensors that drive around at night to measure the tracks. Would have prevented that disaster in Spain.
A 450kph limit for the rolling stock is great, but how many lines are actually capable of these speeds? There's only a single line (Chengdu–Chongqing, currently under construction) which is designed for 350kph, with sections capable of 400kph. Aside from that, most lines are at 350kph - unless I'm missing something.
By garte 2026-03-0314:34 This is how you start something and get progress.
More lanes on the highway are not progress.
Wow I though 300 Kph was some kind of physical limit. I mean every high speed train in the world used to max out at 300.
Now it feels like it was just lack of competition. Maybe now other countries will start producing lines and trains capable of 400 Kph and hopefully its not a China only thing going forward.
There is show and there is reality: French TGV achieved 574,8 km/h in 2007 for show, but it was under specific conditions, not in real world conditions.
While it is technically proven that it is possible to do 400+km/h on rail, it's not practical: maintenance, wear, noise, turns, embranchement, and overall cost, ... many considerations that are probably less important for Chinese railway now, which needs some "show".
By litbear2022 2026-03-041:43 You should update your data; in 2013, China's high-speed rail reached 605 km/h on experimental lines. The CR450 is scheduled to enter commercial service in 2026.
By whinvik 2026-03-0320:11 Sorry if I wasn't clear but was not talking about demo runs. There are plenty of those. Was more meaning operational speeds having a limit.
Like pretty much everything else, it's an optimization problem rather than a physical limit.
So running a train at 350kph is more expensive than 300kph, both in per-distance and pre-unit time terms. But if you can run more services that way then sufficient demand might make it economical. Also, if it's too slow, people may choose flying instead.
Maglev can go even faster but those have never been made economical, really. It's much more complicated and expensive.
It's a bit like how commercial planes have actually gotten slower. 747s used to fly closer to Mach 0.9. Now most commercial planes fly at around Mach 0.8. There are physical problems flying between Mach 0.8 and 1.2 but sometimes that doesn't matter so the best private planes top out at about Mach 0.93. Even then they rarely fly that fast.
By bob1029 2026-03-0314:02 In the case of private jets, the Mach figure is mostly a proxy for other performance metrics.
Flying an aircraft at max cruise can save a lot of time on longer flights, but it's also substantially more expensive.
300kph is the limit because aerodynamics make that about the best compromise on the effeciency cury. higher speeds are completely possibly - but air planes running with much less atmospheric drag start to become the better option.
of course the above is all about compromise and you can emphasize whatever numbers you want to get different results.
Edit: it is often a good idea to have everything capable of faster speeds - say 350km/h. You don't normally want to use those speeds, but if a train gets delayed (as happens) you can use that extra speed to make up time. Just don't let this become a normal thing.
What about if they added “wings” to trains? That could generate some lift reducing the effective weight is my shower thought.
No idea how much the wings would add versus the lift help.
By NuclearPM 2026-03-0317:43 The friction is almost entirely from drag/air resistance, not from the resistance of the rails.
By bluGill 2026-03-0411:46 the losses from weight are linear with speed - at high speed completely dwarfed by losses from pushing air out of the way which is quadradic with speed.
the wings on race cars are poited down - they increase weight to keep the car on the ground at the expense of more drag, which they overcome with a bigger engine (and more fuel use)
By Kuinox 2026-03-0313:07 The French TGV managed to reach 574km/h, so 300km/h is not an hard limit. https://www.youtube.com/watch?v=EOdATLzRGHc
