China Solves 'Tunnel Boom' Problem With Maglev Trains (theguardian.com)
- Reference: 0178608894
- News link: https://tech.slashdot.org/story/25/08/08/0045208/china-solves-tunnel-boom-problem-with-maglev-trains
- Source link: https://www.theguardian.com/environment/2025/aug/07/maglev-train-researchers-may-have-solved-tunnel-boom-shock-waves
> The newest version of the maglev train is capable of traveling at 600km/h (about 370mph). However, the train's engineers have wrestled with the problem of the shock waves which occur as the train exits the mouth of a tunnel. When a high-speed train enters an enclosed space such as a tunnel, air in front is compressed, like in a piston. The resulting fluctuations in air pressure coalesce at the tunnel mouth, generating low-frequency shock waves. These are colloquially known as a " [2]tunnel boom " -- a related, albeit different phenomenon to the "sonic boom" heard as aircraft pass the speed of sound. Tunnel booms pose serious challenges to operational safety, as the shock waves can disturb humans and animals nearby, as well as causing structural damage.
>
> Now, however, researchers have discovered that placing innovative soundproofing buffers at tunnel mouths [3]can reduce shock waves by up to 96% . This promises improvements in operational safety, noise pollution and passenger comfort, as well as safeguarding animals in the vicinity of future lines. [...] The porous structure of the new 100-meter long buffers, combined with porous coatings on the tunnel body, allow the trapped air to escape before the train reaches the tunnel mouth, suppressing the boom in the same way as a silencer fitted to a firearm.
[1] https://slashdot.org/~Epeeist
[2] https://en.wikipedia.org/wiki/Piston_effect#Tunnel_boom
[3] https://www.theguardian.com/environment/2025/aug/07/maglev-train-researchers-may-have-solved-tunnel-boom-shock-waves
When dictators lead in innovation (Score:2)
and innovators turn to dictatorship.
Re:When dictators lead in innovation (Score:4, Interesting)
People have been touting China as the next world leader, displacing the US, since the 90s. Earlier possibly.
They thought it would happen economically and we all would start learning the communist ways.
What I think is more likely to happen is that China will see major societal turmoil in the next two decades, toppling the authoritarian government and then it will become the land of the free and the home of the brave.
Meanwhile the complacent west will go through a phase of relearning the value of what it used to have. It will do us a lot of good and it'll prime us to take world leader role at a later date... But it will be painful as valuable lessons usually are.
Re: (Score:3)
The idea that the population and resources of China will make it a world leader as soon as it reaches enough technology, is the main thesis of the essay "When China awakes, the world will tremble" (Alain Peyrefitte, 1973). Though it sold 800k copies in the original French, this particular essay was apparently not translated. [His later work The Immobile Empire (1989), more critic against China, was read in numerous countries.]
Re: (Score:2)
While interesting as far as factoids go, I'm not sure what you think the impact on my take on matters would be.
I don't think that China's limitation is technology. The whole world is already dependent on its workforce and resources.
China is what enables tech bros to shine. Hell, how many of our scientists are Chinese born bringing with them Chinese work ethics.... and Chinese ethics?
The latter is the issue. Nobody trusts China and for damn good reason. If China manages to ease up and become a high trust soc
Re: (Score:2)
Despite their issues, I think China supplanting the US as the world's largest economy is pretty much a given at this point. While the remaining western governments, quite rightly, have reservations over how trustworthy and reliable China might be as an economic partner, the reality is that's just a matter of degrees and ultimately every country is mostly looking out for #1. The only difference is the lengths they are prepared and able to go to achieve their aims; some much more so than others.
Establing
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But I am not talking about outgrowing the economy. Simple dollar values are hollow. China already is totally entrenched in just about every supply chain.
Intel is dying both on the planning and production side of chips. The latter is in Taiwan's hand. If China pulls its head out of its arse, the animosity between it and Taiwan may go up in smoke faster than people want to believe and what then?
As I said elsewhere, if China manages to convince the world it's turning into a high trust society while America is
Re: (Score:2)
> Meanwhile the complacent west will go through a phase of relearning the value of what it used to have. It will do us a lot of good and it'll prime us to take world leader role at a later date
You are speculating, and I will speculate even further. If there is a Western renaissance, it will be without the US. Reading the international papers, it is apparent that the US is now regarded as unreliable and a dubious ally. Other alliances are being formed, and other trading partnerships, and there are discussions going on about reducing the reliance on the US.
Re: (Score:2)
Well the words "What I think is more likely to happen" both flag my post as speculation and a personal opinion.
And I agree with you. Since we've given the US quasi leadership of the western world, it giving up world dominance automatically means we as its sycophants won't have a pole position to take over, especially since the same societal issues ail us as do them.
That's why I said in the future we may bounce back but in what way I am unable to say. Perhaps it's gonna be the EU or perhaps either France or
Re: (Score:2)
That's because you reason like a Westerner. There may be protests and changes in China, but not necessarily in the way you imagine with a shift towards the West.
Re: (Score:2)
I don't want them to shift toward the west.
I said I expect them to become a high trust society. While I am personally convinced that we were a high trust society in most parts due to the catholic Church, I would not discount the chance that other cultures can build one as well.
I would also not discount the chance that Catholicism actually ticks up in China at some point. Again, I wouldn't wager on the precise mechanisms... I'm just saying that the instability that is becoming ever more aparent in China CAN
Re: When dictators lead in innovation (Score:3)
That sort of implicitly assumes that our way, the way of the west, is the only stable way. A very comforting and soothing thought.
Maybe it is more complicated than what we were taught. Especially with one country going full speed nazi... again.
Stick with trouble...
Re: (Score:1)
I bet you have no clue what you are talking about. I am pretty sure you have not read Mein Kampf for starters.
Re: When dictators lead in innovation (Score:2)
Could be.
Re: (Score:2)
The underlying assumption is that a people's desire for freedom will always win out.
There seems to be a non-zero chance that present-day China has managed to find the thin edge where their people have just enough freedom to not get grumbly.
It's not impossible that this is not actually true, but it might only fall apart in a hundred years or so.
Re: (Score:2)
A lot of young people are disillusioned with capitalism, and quite understandably so. It hasn't delivered the benefits for them, and the advice they were giving about making it work (get educated, get a house, work hard and rewards will come) turned out to be bad.
They look at China, which provides for citizens. When they see that people are going to migrate to cities, they build big new cities with affordable housing and excellent public transport. Meanwhile in the West it's all landlords, who are also NIMB
Japanese solution. (Also, fans?) (Score:2)
Japanese solution -- I saw a YouTube video on how the Japanese addressed this by elongating the nose of the Shinkansen. That design was inspired by the kingfisher bird diving in water. The length of the nose helps to gradually displace the air as it enters the tunnel, reducing the strength of the pressure wave.
Also, perhaps fans could be a solution. Powerful blowers that push air out one end of the tunnel, just as the train enters in at the other end, then taper to zero as the train exits
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Hmm, count the number of tunnels and compare it with the number of locomotives, then read up on other high speed train nose designs.
Makes sense (Score:4, Interesting)
Bullet silencer technology applied to a bullet train. Makes sense.
Too bad the article lacks images though.
Contemporary Shinkansen trains reduce tunnel boom by elongated noses, inspired by the beaks of birds who can dive from the air into water without causing ripples on the surface.
Re: (Score:3)
It must be more than just the gun silencer concept, because the Japanese tried that with limited success for their conventional high speed trains.
The Chinese seem to have applied some new materials to absorb the sound.
The Japanese must be quite worried about developments in China. Theirs was going to be the only long distance maglev system, and a lot of the financing was based on being able to export the technology. China is going to beat them to deployment and will doubtless export the technology too. Now