6 ms·

I'm not exactly impressed by this analysis. I don't recall anyone questioning whether putting a cylinder in a vacuum tube was possible, mainly that it would be

by misnome 13y ago

I'm not exactly impressed by this analysis. I don't recall anyone questioning whether putting a cylinder in a vacuum tube was possible, mainly that it would be horrendously difficult to design, build, tunnel, and reach the high safety margins required, relatively inefficient compared to the alternatives, and that there was lots and lots of hand waving over the real details. They've simulated a vacuum tube, and found that it works.

InclinedPlane 13y ago
If you'd actually described any relevant aspect of Hyperloop your criticism might have more credibility, as it stands it has none. Hyperloop is not a vacuum tube train, and the primary mechanism it relies on is non-trivial.
- tptacek 13y ago
  In your rush to point out the error he made about vacuum tubes, you missed his point, which is that the criticisms of the Musk plan don't revolve around the concept being infeasible to execute, but rather that the concept isn't cost-effective or, for that matter, nearly as customer-friendly as the proposal suggests. Specific points that you'd want to address if you were purporting to rebut Hyperloop criticisms: * Because Musk's plan can't leverage existing last-mile infrastructure the way HSRs do, it delivers riders from one very inconvenient location to another, adding 1-2 hours of additional transit time to SF-LA. * Because (by Musk's own admission) destructive disruptions of his pod-in-tube runs are catastrophic in a way that they aren't with HSRs, his plan requires TSA-style airport security, adding an additional 15-30 minutes to every trip. * The cost estimates for the Hyperloop captured only its capex costs and not its operating expenses, so that the per-ticket prices derived from its proposed cost bore no relation to its actual cost structure. * That the tunneling and viaduct cost estimates given in the Hyperloop proposal were so low that they constituted a revolutionary breakthrough in urban planning and structural engineering in their own right; in other words, if he can dig a Hyperloop-capable tunnel for the price his plan suggests, or run an elevated tube as cheaply as he suggests, why waste time with Hyperloops? The answer would be that he can't do either of those things. * That the routing he proposes, particularly with regards to mountain passes, are wildly optimistic, and that a realistic routing will result in a longer run and significantly increased costs. * That the forces involved on passengers in the Hyperloop exceed the tolerances allowed for existing HSRs in ways that are likely to make motion sickness a signficant problem. This article appears to address none of them, and your comment appears to be premised on the idea that those criticisms hadn't been made.
  - wavesounds 13y ago
    None of these seem impossible to overcome. The current proposed HSR is targeted at $60-100 billion, the estimate for Hyperloop was $9 billion. I find it hard to believe that Elon Musk who sent a rocket to an orbiting space station would be off in his calculations by the 550%-1000% needed reach the price of HSR. So I think we should be impressed by the results of this study and get on with more studies to address the additional concerns tptacek posted. Edit: I'm not trying to rebut or argue about any of the challenges. I'm just saying I find it highly unlikely any of them are 50+ billion dollar problems.
    - tptacek 13y ago
      "Because Elon Musk" is not a real rebuttal to any argument. A somewhat cynical but I think on-the-money assessment of the Hyperloop is that it isn't at all a real proposal, but rather a sleight of hand to reduce buy-in to the CA HSR plan, which Musk opposes. That being the case, investing money in further studies seems like a dumb plan. Extraordinary claims require extraordinary evidence, and there are extraordinary claims in Musk's proposal with no evidence backing them up, so the onus is probably on him.
      - tod222 13y ago
        > it isn't at all a real proposal, but rather a sleight of hand to reduce buy-in to the CA HSR plan, which Musk opposes. Absolutely. People familiar with the tech industry should recognize this pattern: Announce a vaporware [1] product as part of a FUD [2] campaign against the enemy. When considered in this way, Musk's actions with Hyperloop make a lot of sense. This is a classic FUD move against CA HSR. [1] http://en.wikipedia.org/wiki/Vaporware http://en.wikipedia.org/wiki/Vaporware [2] http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt
        9999 13y ago
        In what way are Musk's criticisms of the CA HSR plan FUD? Frankly, the HSR plan is a dud, and his criticisms are largely, if not entirely, valid. The cost is astronomically high, as a result of that the ticket costs will be greater than airfare. The route they've chosen also means that the journey will take far longer than it should. Would you actually consider taking a 2 hour 38 minute train trip from LA to SF at > $200 round-trip? Even if Musk's Hyperloop proposal remains only a proposal, if nothing else it should give people serious pause about the existing plan, and hopefully force a revision of it. The route through Palmdale is utterly pointless, tacks on a dozen minutes to a trip that's already too long, and exists largely to satisfy NIMBYs and give fat checks to a bunch of property speculators. That particular element of the HSR plan reeks of cowardice, corruption and graft. Consider this as an alternative: http://www.cahsrblog.com/2013/06/the-truth-about-tejon/ http://www.cahsrblog.com/2013/06/the-truth-about-tejon/ Musk's opposition to the existing plan is well reasoned and rational. Calling it FUD is itself a sort of FUD.
vwinsyee 13y ago
There is no (hard) vacuum tube in the Hyperloop design. This analysis did not simulate a (hard) vacuum tube.
- derekp7 13y ago
  This is actually one of my biggest disappointments with the Hyperloop announcement. Musk said early on that it wasn't a vacuum tube. But in the end, we have a tube with vacuum pumps, and an air pressure much lower than that of Mars. In my book, that is close enough to a vacuum tube that it sounds like purposeful mis-direction on Musk's part. I.e., when he said (when he first mentioned the idea) that it isn't a vacuum tube, it would have been more honest to say that it isn't a complete hard vacuum tube. Would have cut out on some of the more wild speculations.
  - mapt 13y ago
    "Vacuum tube", aside from being a complete misnomer that's more usually applied to 'pneumatic tube', betrays the concept in one particular area: It's a battery-powered hovercraft inside of a soft vacuum tube (soft vacuum being within reasonable reach of cheap pumps), with boost segments to get it up to speed. Usually, vacuum concepts rely purely magnetic levitation & propulsion. The fact that it's an air cushion vehicle in a soft vacuum IS the novel concept here.
    - EEGuy 13y ago
      mapt, this. Maybe I should do the math, but I can't imagine magnetic levitation (not propulsion) running off on-board batteries.
  - Retric 13y ago
    While it might seem like a vacume the amount of air left in the tube makes it far cheaper to operate. It's one of those 1 +/- .001 foot rod is not that expencive but a 1 +/- .0001 foot rod is getting there and a 1 +/- .00001 foot rod even more so. Basicly vacume pumps cost more, use more energy, become more delicate, and move less air the closer you get to hard vacume. However, there is still plenty of air in the tube to be an issue at the proposed speeds thus making Hyperloop cheaper and more complex than a traditional vacume transport.
peatmoss 13y ago
As a planner, my biggest questions are around land acquisition. It's not usually the kit that's the super expensive part of these projects. That said, I suppose it's possible that the land requirements for the hyperloop are less. I meet a lot of curmudgeonly planners who like to downplay the potential impacts of new technology (hyperloop, self-driving cars, etc.), but I'm open to the possibility of truly disruptive tech. Still, I have a hard time imagining that the land acquisitions will be that much cheaper for hyperloop.
- vidarh 13y ago
  A large point of the proposal was the massively reduced land use requirements coming from using a structure on pylons, and from having most of it follow the existing highway on land that's already publicly owned. The assumptions regarding land use were pretty well covered in the PDF Elon Musk released.

by misnome 13y ago

InclinedPlane 13y ago

If you'd actually described any relevant aspect of Hyperloop your criticism might have more credibility, as it stands it has none. Hyperloop is not a vacuum tube train, and the primary mechanism it relies on is non-trivial.

tptacek 13y ago
In your rush to point out the error he made about vacuum tubes, you missed his point, which is that the criticisms of the Musk plan don't revolve around the concept being infeasible to execute, but rather that the concept isn't cost-effective or, for that matter, nearly as customer-friendly as the proposal suggests. Specific points that you'd want to address if you were purporting to rebut Hyperloop criticisms: * Because Musk's plan can't leverage existing last-mile infrastructure the way HSRs do, it delivers riders from one very inconvenient location to another, adding 1-2 hours of additional transit time to SF-LA. * Because (by Musk's own admission) destructive disruptions of his pod-in-tube runs are catastrophic in a way that they aren't with HSRs, his plan requires TSA-style airport security, adding an additional 15-30 minutes to every trip. * The cost estimates for the Hyperloop captured only its capex costs and not its operating expenses, so that the per-ticket prices derived from its proposed cost bore no relation to its actual cost structure. * That the tunneling and viaduct cost estimates given in the Hyperloop proposal were so low that they constituted a revolutionary breakthrough in urban planning and structural engineering in their own right; in other words, if he can dig a Hyperloop-capable tunnel for the price his plan suggests, or run an elevated tube as cheaply as he suggests, why waste time with Hyperloops? The answer would be that he can't do either of those things. * That the routing he proposes, particularly with regards to mountain passes, are wildly optimistic, and that a realistic routing will result in a longer run and significantly increased costs. * That the forces involved on passengers in the Hyperloop exceed the tolerances allowed for existing HSRs in ways that are likely to make motion sickness a signficant problem. This article appears to address none of them, and your comment appears to be premised on the idea that those criticisms hadn't been made.
- wavesounds 13y ago
  None of these seem impossible to overcome. The current proposed HSR is targeted at $60-100 billion, the estimate for Hyperloop was $9 billion. I find it hard to believe that Elon Musk who sent a rocket to an orbiting space station would be off in his calculations by the 550%-1000% needed reach the price of HSR. So I think we should be impressed by the results of this study and get on with more studies to address the additional concerns tptacek posted. Edit: I'm not trying to rebut or argue about any of the challenges. I'm just saying I find it highly unlikely any of them are 50+ billion dollar problems.
  - tptacek 13y ago
    "Because Elon Musk" is not a real rebuttal to any argument. A somewhat cynical but I think on-the-money assessment of the Hyperloop is that it isn't at all a real proposal, but rather a sleight of hand to reduce buy-in to the CA HSR plan, which Musk opposes. That being the case, investing money in further studies seems like a dumb plan. Extraordinary claims require extraordinary evidence, and there are extraordinary claims in Musk's proposal with no evidence backing them up, so the onus is probably on him.
    - tod222 13y ago
      > it isn't at all a real proposal, but rather a sleight of hand to reduce buy-in to the CA HSR plan, which Musk opposes. Absolutely. People familiar with the tech industry should recognize this pattern: Announce a vaporware [1] product as part of a FUD [2] campaign against the enemy. When considered in this way, Musk's actions with Hyperloop make a lot of sense. This is a classic FUD move against CA HSR. [1] http://en.wikipedia.org/wiki/Vaporware http://en.wikipedia.org/wiki/Vaporware [2] http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt
      - 9999 13y ago
        In what way are Musk's criticisms of the CA HSR plan FUD? Frankly, the HSR plan is a dud, and his criticisms are largely, if not entirely, valid. The cost is astronomically high, as a result of that the ticket costs will be greater than airfare. The route they've chosen also means that the journey will take far longer than it should. Would you actually consider taking a 2 hour 38 minute train trip from LA to SF at > $200 round-trip? Even if Musk's Hyperloop proposal remains only a proposal, if nothing else it should give people serious pause about the existing plan, and hopefully force a revision of it. The route through Palmdale is utterly pointless, tacks on a dozen minutes to a trip that's already too long, and exists largely to satisfy NIMBYs and give fat checks to a bunch of property speculators. That particular element of the HSR plan reeks of cowardice, corruption and graft. Consider this as an alternative: http://www.cahsrblog.com/2013/06/the-truth-about-tejon/ http://www.cahsrblog.com/2013/06/the-truth-about-tejon/ Musk's opposition to the existing plan is well reasoned and rational. Calling it FUD is itself a sort of FUD.

vwinsyee 13y ago

There is no (hard) vacuum tube in the Hyperloop design. This analysis did not simulate a (hard) vacuum tube.

derekp7 13y ago
This is actually one of my biggest disappointments with the Hyperloop announcement. Musk said early on that it wasn't a vacuum tube. But in the end, we have a tube with vacuum pumps, and an air pressure much lower than that of Mars. In my book, that is close enough to a vacuum tube that it sounds like purposeful mis-direction on Musk's part. I.e., when he said (when he first mentioned the idea) that it isn't a vacuum tube, it would have been more honest to say that it isn't a complete hard vacuum tube. Would have cut out on some of the more wild speculations.
- mapt 13y ago
  "Vacuum tube", aside from being a complete misnomer that's more usually applied to 'pneumatic tube', betrays the concept in one particular area: It's a battery-powered hovercraft inside of a soft vacuum tube (soft vacuum being within reasonable reach of cheap pumps), with boost segments to get it up to speed. Usually, vacuum concepts rely purely magnetic levitation & propulsion. The fact that it's an air cushion vehicle in a soft vacuum IS the novel concept here.
  - EEGuy 13y ago
    mapt, this. Maybe I should do the math, but I can't imagine magnetic levitation (not propulsion) running off on-board batteries.
- Retric 13y ago
  While it might seem like a vacume the amount of air left in the tube makes it far cheaper to operate. It's one of those 1 +/- .001 foot rod is not that expencive but a 1 +/- .0001 foot rod is getting there and a 1 +/- .00001 foot rod even more so. Basicly vacume pumps cost more, use more energy, become more delicate, and move less air the closer you get to hard vacume. However, there is still plenty of air in the tube to be an issue at the proposed speeds thus making Hyperloop cheaper and more complex than a traditional vacume transport.

peatmoss 13y ago

As a planner, my biggest questions are around land acquisition. It's not usually the kit that's the super expensive part of these projects. That said, I suppose it's possible that the land requirements for the hyperloop are less. I meet a lot of curmudgeonly planners who like to downplay the potential impacts of new technology (hyperloop, self-driving cars, etc.), but I'm open to the possibility of truly disruptive tech. Still, I have a hard time imagining that the land acquisitions will be that much cheaper for hyperloop.

vidarh 13y ago
A large point of the proposal was the massively reduced land use requirements coming from using a structure on pylons, and from having most of it follow the existing highway on land that's already publicly owned. The assumptions regarding land use were pretty well covered in the PDF Elon Musk released.