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View Diary: Lies, Damned Lies, And Hyperloop (94 comments)

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  •  The diameter hardly matters (1+ / 0-)
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    terrypinder

    for most of the logistics. Having a post in the middle of a road or building is kind of a big deal.

    They have to be sunk into the ground and they have to be broad enough to resist a moment force when the dynamic load comes through which includes both the transport cars and earthquakes, potentially simultaneously. If they're not in protected locations, you have to imagine that they might be hit by vehicles on the ground, and fortify them against that.

    But all that said... 58 tons plus the weight of a large steel pipe, 20 feet in the air? A regular passenger car, for comparison, weighs two tons. That's a lot of force when you shake it.

    There's no getting away without creating disruption in the urban area.

    Fry, don't be a hero! It's not covered by our health plan!

    by elfling on Tue Aug 20, 2013 at 08:42:49 AM PDT

    [ Parent ]

    •  Oh, and after that significant dynamic loading (1+ / 0-)
      Recommended by:
      terrypinder

      the pipes still have to hold a vacuum. Not a lot of room for error.

      Fry, don't be a hero! It's not covered by our health plan!

      by elfling on Tue Aug 20, 2013 at 08:43:38 AM PDT

      [ Parent ]

      •  Amazing how after all this, (1+ / 0-)
        Recommended by:
        aseth

        you're still under the mistaken impression that the system is based on a vacuum.  How many times has this misconception been corrected here?  How is it you're still missing this?  For the Nth time, where N approaches infinity, Hyperloop is not based on evacuated tubes.  Pressure is maintained at roughly the equivalent pressure of 50km altitude, the height of high-altitude balloon flights (think balloons work in a vaccuum?)

        Now, back to your posts.  Yes, the pressure is reduced inside versus outside.  But it's also inch thick steel.  That's way more than adequate to handle a pressure differential.

        Having a post in the middle of a road or building is kind of a big deal.
        Apparently you don't know what a median is. Here, have a satellite view of the proposed route.  For the overwhelming majority of the trip, that's what it looks like.  
        They have to be sunk into the ground and they have to be broad enough to resist a moment force when the dynamic load comes through which includes both the transport cars and earthquakes, potentially simultaneously.
        Yes, all structures have to be built with an error margin to handle disasters.  The error margin is proportional to the weight of the structure (aka, you don't have a 1-pound elevated structure with 3000 tonnes of margin, nor a 3000 tonne elevated structure with 1 pound of margin).  So this line of argument buys you nothing, because it still comes down to the base load requirements, which are predominantly due to the mass of the vehicles.  And hyperloop pods are a fraction of a percent of the mass of a HSR train.
        They have to be sunk into the ground and they have to be broad enough to resist a moment force when the dynamic load comes through which includes both the transport cars and earthquakes, potentially simultaneously. If they're not in protected locations, you have to imagine that they might be hit by vehicles on the ground, and fortify them against that.
        I could build a berm that would stop a semi by digging for a day with a backhoe.  It's a non-issue.
        But all that said... 58 tons plus the weight of a large steel pipe, 20 feet in the air? A regular passenger car, for comparison, weighs two tons. That's a lot of force when you shake it.
        58 tonnes is about the weight of a loaded semi.  The pipe is of similar mass between spans.  A HST train is many thousands of tonnes.  The forces involved are simply incomparable.  Which makes comparisons of the costs of rail viaducts to the cost of Hyperloop pillars absurd.

        Here, let's put it another way.  Hyperloop loading is similar to that of Disney's monorail (empty six-car monorail = 50 tons, plus passengers, track mass should be similar to that of 2 1" tubes...)  Here's the sort of pillars you need to support it:

        Notice how small of a footprint the columns are?  Notice how thin that piece of metal that's actually holding the track is?  It doesn't take much to bear that kind of weight.  Monorail columns are 110 feet apart and the trains are of similar height to Hyperloop.

        Now here's a concrete rail bridge with half as much spacing, about 50 ft (aka, making the job twice as easy)

        On the other end of the specturm, here's about 200-foot spacing:

        Notice a wee difference here versus what monorail-level loadings require?  Starting to understand why rail cost figures are not applicable for Hyperloop elevation costing?

        And hey, let's talk about the Disney Monorail, shall we, since we're talking about a similar construction profile and loading requirements.  It cost $1m a mile in the 1970s - first of its kind and employing all sorts of new techniques.  If we go with a 3x inflation rate and 350 miles, that's $950m in today's money for the length of the proposed route.  Except that hyperloop track is overall simpler than monorail track (columns are a bit more complex, and the specifications tigher, but the "track" itself is simpler except in short areas (accelerator, emergency exists, pumps, etc - but there's many miles of spacing between these); it has 20 times the length (aiding mass production, which drives down costs); and it can make use of modern mass production techniques.  And how much does Musk budget for tubes plus columns?  $3.2 billion

        Once again, I ask you, tell me what is so unrealistic about Musk's figures?  And why do you keep insisting on using figures that clearly are not applicable to a system with mass and size figures on the order of Hyperloop's?

        Já þýðir já. Nei þýðir nei. Hvað er svona erfitt við það?

        by Rei on Tue Aug 20, 2013 at 09:45:51 AM PDT

        [ Parent ]

        •  Rei, I live here, I drive I-5 all the time (1+ / 0-)
          Recommended by:
          terrypinder

          I grew up driving the Newhall Pass daily. I know not only what it looks like, but that the ground isn't as flat as it looks, that there are overpasses that cross the freeway, that the logistics around what seems like a simple project of adding freeway lanes in an existing median seem to always involve bridge modifications and lots of pesky details.

          It's the details that kill you. It's just like building a house (or a software program!) where 90% of the project goes in quickly and easily... and it looks done!... and the last 10% takes the second half of the time and money. If not more.

          Pillars the size of the monorail are just what I had in mind. It's going to cost a lot of money to plunk them down through the Newhall Pass and into Sylmar, and way way more if you wanted to get to, say, Burbank. There's stuff in the way. The ground is unstable. You need a lot of pillars.

          The Disney Monorail is a very cool system, but located on private property and as a non-essential service... it has tremendous advantages in the logistics of building it over a 400 mile public works program that has to have 100% uptime.

          I don't know why you're so invested in this, or why you feel the need to be so scathing. All anyone is saying is that transportation projects are expensive and take way more time and money than one expects, even when using proven, well understood technology. When you're building new technology on a scale like this, there are always surprises. Always. (If there weren't, it wouldn't be fun! :-) )

          If Musk believes in this, he'll invest in it and kick it forward regardless of what anyone writes here. And I'm all for full employment of engineers. Some of my good friends work for him already. As I said, there are plenty of places that need high speed transport and CAHSR will only show the need and create demand for more of the same.

          We don't want to stop an existing project that is ready to break ground for a speculative white paper. That's because we'd like to have a system up and running before our kids are collecting Social Security. It's already been far too long.

          Fry, don't be a hero! It's not covered by our health plan!

          by elfling on Tue Aug 20, 2013 at 11:25:45 AM PDT

          [ Parent ]

          •  thank you elfling. :) (0+ / 0-)

            I'm not an engineer--I sit on the other side (the side that holds the purse). I'm not too keen on the technical sides that Alon Levy and others are pointing out. But the cost estimate is glaringly wrong. But, as the document says, it's an alpha-release and it's "open-source." It's not even by far a final product.

            Dawkins is to atheism as Rand is to personal responsibility- mperiousRex. tropical weather season is here

            by terrypinder on Tue Aug 20, 2013 at 12:06:14 PM PDT

            [ Parent ]

          •  Re: (1+ / 0-)
            Recommended by:
            aseth
            I grew up driving the Newhall Pass daily. I know not only what it looks like, but that the ground isn't as flat as it looks,  that there are overpasses that cross the freeway,
            Hence the reason for varying height on pillars, as discussed and  in the document.
            that the logistics around what seems like a simple project of adding freeway lanes in an existing median seem to always involve bridge modifications and lots of pesky details.
            Columns are dramatically simpler than lanes.
            It's the details that kill you.
            Which is why you go with figures from existing systems and go pessimistic on your numbers.  Which I've done here, showing comparable construction projects to Musk's (rather than the absurd comparisons with tunnels many times the size and viaducts with capacities orders of magnitude higher), and I'm still waiting for an opponent to for once compare to a comparable construction task.  His tube cost are 3x that of the steel.  His tube plus pillars cost is 3x that of the similar-pylon-supported similar-weight-bearing monorail.  We're not talking land acquisition here in either case.  These are the sort of pessimistic figures one responsibly budgets.
            It's going to cost a lot of money to plunk them down through the Newhall Pass and into Sylmar and way way more if you wanted to get to, say, Burbank. There's stuff in the way. The ground is unstable. You need a lot of pillars.
            First off, it's a median, there shouldn't be "stuff in the way", apart from intersections,  which given the limited access nature of a higway can't be too often.  Secondly, medians are already nice and cleared, unlike what the people building the Monorail faced.  Third, soil stability figures will of course vary on a 350 mile project; it's averages that matter.
            The Disney Monorail is a very cool system, but located on private property
            Irrelevant since we're discussing construction cost figures here, not land acquisition, both in terms of the figure given for the Monorail and the figure given for Hyperloop.
            and as a non-essential service...
            At several million of passengers per year, it serves more than the LA/SF air route.  While it's not essential,  Disney World's monorail pretty much is, and serves 50 million per year (busiest monorail in the world).  
            it has tremendous advantages in the logistics of building it over a 400 mile public works program that has to have 100% uptime.
            Right, because transit departments famously care about 100% uptime, but companies making big money on every passenger who walks in their doors don't?
            I don't know why you're so invested in this, or why you feel the need to be so scathing.
            Because I see people making ridiculous claims about a tech proposal that I feel has huge potential for transit time and cost reduction, and of course I naturally want to respond.
            If Musk believes in this, he'll invest in it and kick it forward regardless of what anyone writes here.
            Maybe some day.  But given the flack he took from SpaceX investors when he started a second big company (Tesla), and how he's pretty much got all his money wrapped up in them, I imagine it'll be years before he could personally do it.  

            Já þýðir já. Nei þýðir nei. Hvað er svona erfitt við það?

            by Rei on Tue Aug 20, 2013 at 03:40:01 PM PDT

            [ Parent ]

        •  You are contradicting yourself. (2+ / 0-)
          Recommended by:
          terrypinder, TheMomCat
          Hyperloop is not based on evacuated tubes.  Pressure is maintained at roughly the equivalent pressure of 50km altitude.
          If pressure is maintained at roughly the equivalent pressure of 50km altitude, and the Hyperloop tube is not at 50km in altitude, then its operating in 1/1000th of an atmosphere.

          That is clearly an evacuated tube. 999/1000th of an atmosphere has been removed, after all. That's 99.9% out, 0.1% remaining.

          And your freight rail bridges as supposed examples of the requirements of HSR trains does undermine your argument in a similar way that the Hyperloop lies about HSR energy consumption undermines its argument.

          Support Lesbian Creative Works with Yuri anime and manga from ALC Publishing

          by BruceMcF on Tue Aug 20, 2013 at 12:31:44 PM PDT

          [ Parent ]

          •  For you. (0+ / 0-)

            1) Go to Google.
            2) Type "evacuated tube"
            3) Hit search.

            Notice what comes up.  "Evacuated tube" = "Vacuum tube".  It's a synonym.

            And your freight rail bridges as supposed examples of the requirements of HSR trains does undermine your argument in a similar way that the Hyperloop lies about HSR energy consumption undermines its argument.
            Mmmhmm.  Care to actually back up your claims, or is it more "proof by boldfaced assertion"?  Care to even explain why a freight rail bridge isn't applicable?  I can't find specific CAHSR weight figures, but they should be in the thousands of tonnes, given rail standards and the stated passenger capacity.  Versus, again, 58 tonnes.

            Já þýðir já. Nei þýðir nei. Hvað er svona erfitt við það?

            by Rei on Tue Aug 20, 2013 at 02:57:59 PM PDT

            [ Parent ]

            •  0.1% atmosphere is a soft vacuum. (0+ / 0-)
              Care to actually back up your claims, or is it more "proof by boldfaced assertion"?  Care to even explain why a freight rail bridge isn't applicable?
              You are using bridges used to hold up trains that are up to a mile long, with axle loadings of 22.5tons, 33tons, 36tons, or even 40tons, with the freight cars of bulk freight trains loaded up to the axle loading capacity of the route ...

              ... to demonstrate the viaduct required for 17ton axle loading trains with eight or sixteen passenger cars, and without or without a power car on either side.

              Asking why they aren't the same is itself a demonstration of your ignorance regarding the subject you are arguing about.

              I can't find specific CAHSR weight figures, but they should be in the thousands of tonnes, given rail standards and the stated passenger capacity.
              So you admit that your argument is based on fact-free supposition.

              Support Lesbian Creative Works with Yuri anime and manga from ALC Publishing

              by BruceMcF on Wed Aug 21, 2013 at 10:47:38 AM PDT

              [ Parent ]

            •  Every engineer and scientist I know (0+ / 0-)

              would colloquially call a device that can create that very low pressure environment (1 millibar) a vacuum chamber, though they would understand it's a rough/soft vacuum.

              The good news is that your pumps don't have to be as fancy. You don't have to worry so much about grease molecules being liberated and coating everything. The bad news is that your chamber integrity still has to be pretty good.

              Fry, don't be a hero! It's not covered by our health plan!

              by elfling on Wed Aug 21, 2013 at 11:17:44 AM PDT

              [ Parent ]

    •  Indeed, ... (0+ / 0-)

      ... if you take the projected increase in cost of pylons when you increase the dynamic load from the Multiloop pass-only to pass+car, and project that through to the dynamic load for a full sized HSR ...

      ... you get an unrealistically low estimate of the cost of a pylon for HSR.

      Support Lesbian Creative Works with Yuri anime and manga from ALC Publishing

      by BruceMcF on Wed Aug 21, 2013 at 11:05:55 AM PDT

      [ Parent ]

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