6 ms·

There's nothing physically impossible about the Hyperloop (basically a maglev in vacuum tube, nothing wrong with the tech, just not particularly economical). Ma

There's nothing physically impossible about the Hyperloop (basically a maglev in vacuum tube, nothing wrong with the tech, just not particularly economical). Maglevs have been deployed successfully in some parts of Asia, they are just dreadfully expensive and nimbys have fears about radiation but they are hardly new technology.

renox 3y ago
Nobody said they're impossible but believing that they would make sense economically even after they switched to maglev was the dumb part.
tsimionescu 3y ago
Note that the main point about the hyperloop was the vacuum tube, not the maglev part. And the vacuum tube doesn't actually work. It's not actually feasible to create a vacuum tube hundreds of km long. It's just about physically possible, but it's not really technologically feasible - not for a system that is supposed to be in constant operation all year long. It's also important to remember that vacuum tube trains are an 1800s idea, which everyone started pretending is some revolutionary new transportation concept.
- jacquesm 3y ago
  And besides that you don't have to have a really good vacuum, you just have to have a 'good enough' vacuum that you can attain high speed without losing the stabilizing effect of a bunch of air constrained by the walls of a tube. Bonus points of you can get the air to move at a speed a bit slower than your vehicle, more bonus points if you can use the air to propel your vehicle. But: it's probably still a dumb idea, but one that is borderline.
  - Kye 3y ago
    I'm still waiting on the giant pneumatic tubes from Futurama.
  - XorNot 3y ago
    The problem is that if any of that was a good idea, the question is why is the Hyperloop specifically a good idea, but regular old high speed rail is not? What factor are you changing that makes one good, and the other not good enough to get done right now? (the answer of course is nothing: the Hyperloop would be stupidly expensive, and however fast it is wouldn't solve the logistics problem of loading and unloading it - so whatever quote you've seen for rail, just triple it if you tried to build a hyperloop).
    - jacquesm 3y ago
      Yes, there isn't anything in particular about Hyperloop that makes it stand out, but it is different in high speed rail in that it is underground and so more complex in almost all ways but one: right of way (and possibly aesthetics, which depending on the landscape can matter a lot).
      - Kye 3y ago
        Not a lawyer and might be wrong but as far as I know land rights go all the way to the core in the US, so going underground wouldn't help with right of way. I know, "HN is more than the US," but we seem to have the most trouble with trains.
        jacquesm 3y ago
        I think you're referring to the 'all the way to heaven and all the way to hell' bit. In principle that's true. But in practice mining rights and such have been split off from the right to the land and some reasonable depth underground. And any objection to an easement would be much harder to establish if it doesn't actually affect you. But for those parties that own the underground and mining rights for a given location there could well be a viable opposition to such a development. But that would then risk an eminent domain claim. It's all pretty complex. But I would still assume that going underground is easier than going above ground where the parcels are small and the interests are immediate due to interference with existing activity.
  - tsimionescu 3y ago
    Anything that can be called "a vacuum" is very very hard to achieve in a large volume.
    - jacquesm 3y ago
      Yes. That's why any kind of vacuum solution is likely a non-starter both from a technical and an economical perspective. And the 'obvious' solutions (multiple smaller evacuated chamber that connect as trains pass through) have a whole raft of safety and complexity issues and are going to increase the costs massively.
- naasking 3y ago
  > It's not actually feasible to create a vacuum tube hundreds of km long Why not? It's just a series of smaller sections that must each individually achieve near vacuum.
  - leni536 3y ago
    I think the main problem is that the failure of a small section is a catastrophic failure of the whole system.
    - naasking 3y ago
      I don't see why you can't compartmentalize it exactly like how I described. A leak in one of the ISS's modules wouldn't take down the whole ISS.
      - anonymouskimmer 3y ago
        And then what? The train just stops in the middle of nowhere for however many days until the one chamber is fixed?
        naasking 3y ago
        It returns obviously. Making repair or replacement of damaged sections economical is one of the engineering challenges. This by itself suggests compartmentalizing along the same lines I suggested. It would probably be ideal if you could factory make each section and ship it on a standard truck, but with the growth of additive manufacturing, other possibilities also open up, like 3D printing the large metal container onsite.
        anonymouskimmer 3y ago
        I think you'd have to print it onsite, otherwise you have no gain in the loop being underground as you'd have to dig basically the entire ground up to swap sections.
  - 3y ago
hobs 3y ago
Physically impossible? Maybe, but the vacuum tube part was actually insane. It would have been insanely difficult to maintain a useful enough vacuum over huge distances that the hyperloop was supposed to run. A single failure in such a system could have catastrophic consequences across a huge range. edit: beaten by @tsimionescu by a minute.
fragmede 3y ago
We didn't miss the part where > Musk admitted Hyperloop was about getting legislators to cancel plans for high-speed rail in California. He had no plans to build it https://twitter.com/alexdemling/status/1557221632837505025 https://twitter.com/alexdemling/status/1557221632837505025 https://time.com/6203815/elon-musk-flaws-billionaire-visions/ https://time.com/6203815/elon-musk-flaws-billionaire-visions...

renox 3y ago

Nobody said they're impossible but believing that they would make sense economically even after they switched to maglev was the dumb part.

tsimionescu 3y ago

Note that the main point about the hyperloop was the vacuum tube, not the maglev part. And the vacuum tube doesn't actually work. It's not actually feasible to create a vacuum tube hundreds of km long. It's just about physically possible, but it's not really technologically feasible - not for a system that is supposed to be in constant operation all year long. It's also important to remember that vacuum tube trains are an 1800s idea, which everyone started pretending is some revolutionary new transportation concept.

jacquesm 3y ago
And besides that you don't have to have a really good vacuum, you just have to have a 'good enough' vacuum that you can attain high speed without losing the stabilizing effect of a bunch of air constrained by the walls of a tube. Bonus points of you can get the air to move at a speed a bit slower than your vehicle, more bonus points if you can use the air to propel your vehicle. But: it's probably still a dumb idea, but one that is borderline.
- Kye 3y ago
  I'm still waiting on the giant pneumatic tubes from Futurama.
- XorNot 3y ago
  The problem is that if any of that was a good idea, the question is why is the Hyperloop specifically a good idea, but regular old high speed rail is not? What factor are you changing that makes one good, and the other not good enough to get done right now? (the answer of course is nothing: the Hyperloop would be stupidly expensive, and however fast it is wouldn't solve the logistics problem of loading and unloading it - so whatever quote you've seen for rail, just triple it if you tried to build a hyperloop).
  - jacquesm 3y ago
    Yes, there isn't anything in particular about Hyperloop that makes it stand out, but it is different in high speed rail in that it is underground and so more complex in almost all ways but one: right of way (and possibly aesthetics, which depending on the landscape can matter a lot).
    - Kye 3y ago
      Not a lawyer and might be wrong but as far as I know land rights go all the way to the core in the US, so going underground wouldn't help with right of way. I know, "HN is more than the US," but we seem to have the most trouble with trains.
      - jacquesm 3y ago
        I think you're referring to the 'all the way to heaven and all the way to hell' bit. In principle that's true. But in practice mining rights and such have been split off from the right to the land and some reasonable depth underground. And any objection to an easement would be much harder to establish if it doesn't actually affect you. But for those parties that own the underground and mining rights for a given location there could well be a viable opposition to such a development. But that would then risk an eminent domain claim. It's all pretty complex. But I would still assume that going underground is easier than going above ground where the parcels are small and the interests are immediate due to interference with existing activity.
- tsimionescu 3y ago
  Anything that can be called "a vacuum" is very very hard to achieve in a large volume.
  - jacquesm 3y ago
    Yes. That's why any kind of vacuum solution is likely a non-starter both from a technical and an economical perspective. And the 'obvious' solutions (multiple smaller evacuated chamber that connect as trains pass through) have a whole raft of safety and complexity issues and are going to increase the costs massively.
naasking 3y ago
> It's not actually feasible to create a vacuum tube hundreds of km long Why not? It's just a series of smaller sections that must each individually achieve near vacuum.
- leni536 3y ago
  I think the main problem is that the failure of a small section is a catastrophic failure of the whole system.
  - naasking 3y ago
    I don't see why you can't compartmentalize it exactly like how I described. A leak in one of the ISS's modules wouldn't take down the whole ISS.
    - anonymouskimmer 3y ago
      And then what? The train just stops in the middle of nowhere for however many days until the one chamber is fixed?
      - naasking 3y ago
        It returns obviously. Making repair or replacement of damaged sections economical is one of the engineering challenges. This by itself suggests compartmentalizing along the same lines I suggested. It would probably be ideal if you could factory make each section and ship it on a standard truck, but with the growth of additive manufacturing, other possibilities also open up, like 3D printing the large metal container onsite.
        anonymouskimmer 3y ago
        I think you'd have to print it onsite, otherwise you have no gain in the loop being underground as you'd have to dig basically the entire ground up to swap sections.
- 3y ago

hobs 3y ago

Physically impossible? Maybe, but the vacuum tube part was actually insane. It would have been insanely difficult to maintain a useful enough vacuum over huge distances that the hyperloop was supposed to run. A single failure in such a system could have catastrophic consequences across a huge range. edit: beaten by @tsimionescu by a minute.

fragmede 3y ago

We didn't miss the part where > Musk admitted Hyperloop was about getting legislators to cancel plans for high-speed rail in California. He had no plans to build it https://twitter.com/alexdemling/status/1557221632837505025 https://twitter.com/alexdemling/status/1557221632837505025 https://time.com/6203815/elon-musk-flaws-billionaire-visions/ https://time.com/6203815/elon-musk-flaws-billionaire-visions...