SFO to LA in 30 mins?

Discussion in 'General Discussion | Travel' started by kyunbit, Jul 10, 2013.  |  Print Topic

  1. kyunbit
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    kyunbit Silver Member

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    Didn't find this posted

    "Commuting is a way of life for most Bay Area residents. Many people are accustomed to an hour commute each way without traffic. Some people even commute to Southern California several times a month, spending several hours each way either in the car or fighting through airports. What if there was an alternative to flights and car rides? If it was up to Tesla CEO Elon Musk and a Colorado company, an answer could come sooner than we think."





    http://news.yahoo.com/san-francisco-l-30-mins-proposed-transportation-system-180600043.html
     
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  2. MX

    MX Gold Member

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    Transport based on magnetic levitation is actually an old and abandoned idea. Levitation uses so much electric power that it becomes obscenely wasteful and expensive. The hard infrastructure too should be orders of magnitude pricier than the proposed high speed rail, which is estimated to run $70 billion. For that kind of dough you can probably buy every passenger a private jet.
     
  3. legalalien
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    legalalien Gold Member

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    Maybe.

    Hyperloop is not a garden variety maglev train a la PVG-to-Shanghai-outskirts though. While the proposed HSR will - by 2029 - match what's long been available in many parts of the world today, Hyperloop is an example of thinking outside the box. If I were to guess how the world will travel in 2100, I would likely pick something similar.
     
  4. viguera
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    viguera Gold Member

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    If it was anybody but Musk I would have called it a pipe dream. But that dude has a way to take the craziest ideas and actually make them work, so I'm going to say it's entirely plausible.
     
  5. MX

    MX Gold Member

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    If Musk had a serious interest in such transport he might have done a bit more than a vague description and a drawing. Instead he's just feeding lots of nothing to every news outlet, while carefully inserting a mention of an upcoming "big announcement" from Tesla Motors. Could he be running a Tesla PR campaign without properly paying for advertising space? :eek:
     
  6. MX

    MX Gold Member

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    I'd have to disagree. It's not a matter of vision, but simple physics. At speeds above 75 mph (which is also the hurricane threshold), the resistance of air to movement increases exponentially. The rolling resistance of wheels against rails or ground may only increase slightly and linearly with speed. In examples with hurricanes, doubling the wind speed from 75 (cat.1) to 150 mph (cat.5) changes the effects from spot damage to almost total destruction.

    So if one were to design a logical high speed transport at ground level, fighting gravity (i.e. pushing the train upward as in levitation) would not be a way to propel it forward any faster. An example of real thinking outside the box would be a wind tunnel type of contraption. But again, it's way impractical considering the available alternatives.
     
  7. mattsteg
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    mattsteg Gold Member

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    the tunnel is evacuated.
     
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  8. mattsteg
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    mattsteg Gold Member

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    Elaborating on this, the tunnel is kept at a vacuum in order to avoid dealing with fluid drag. Remove the air, remove the rolling/sliding resistance, and total drag is very low.

    In terms of the wind-tunnel idea...that's a complete nonstarter, due to simple physics. At the very least you run into complete showstoppers due to compressibility starting as you approach the speed of sound, and you need to fight that drag that you're so worried about along the full length of the tunnel walls. Even if you were able to get to very high speeds, heat would quickly become a critical issue.

    I don't think you're in the position to dismiss this concept on grounds of "simple physics". There are plenty of issues, but at least theoretical possibilities to overcome them. The "real thinking outside the box" solution that you propose, on the other hand, has a whole pile of problems that are far more fundamental in nature.
     
  9. TheBOSman

    TheBOSman Silver Member

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    It's probably only 5 minutes San Francisco to Burbank, but they want to make the Angelenos feel comfortable with the new service, so they will have a train equivalent of the 405 causing the train to take far longer than it should to get from the Valley to downtown LAX :D.
     
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  10. MX

    MX Gold Member

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    Indeed a vacuum tunnel would make a difference. I missed that part. It will still not make the project practical, but I would retain that idea as an option.
     
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  11. Mike Reed

    Mike Reed Gold Member

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    Sure it is. Especially at these speeds. Remove the friction and heat of wheels on rail and these high speeds become much more achievable and have far less moving parts to fail due to the same forces.

    We're talking about something that at 1G acceleration would reach 4000mph in just over three minutes.
     
  12. kyunbit
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    kyunbit Silver Member

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    I share your skepticism, since maintaining vacuum is always expensive. It costs a fortune for a small closed experimental space. I can't imagine what would be the costs for a tube that runs 400 miles.

    However, I don't see anything that prevents it in theory
     
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  13. mattsteg
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    mattsteg Gold Member

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    I imagine we're all on the skeptical side for any sort of near-term implementation and long-term is questionable as well.

    Since we're pie-in-the-skying, what about a giant ram accelerator bringing things up to speed?
     
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  14. legalalien
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    legalalien Gold Member

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    Having a tunnel solves other issues though, e.g., limiting access to the tracks and the associated safety concerns. I also don't think you need to maintain high-grade vacuum to get around fluid drag. Perhaps pressurising the tunnel at 45,000 ft. be sufficient?

    Sure, but IMHO this strikes a good balance by being sufficiently ahead of what's currently available and being something I might see in my lifetime. Unlike California High-Speed Rail.
     

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