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Re: [carfree_cities] Re: Fuel-Sipping Trains

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  • J.H. Crawford
    This is all pretty tangential. The basic physics are: It takes lots of energy to accelerate a train, and the total amount of that energy increases with the
    Message 1 of 18 , Jun 14, 2007
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      This is all pretty tangential. The basic physics are:

      It takes lots of energy to accelerate a train, and the
      total amount of that energy increases with the SQUARE
      of the speed.

      It takes lots of energy to drag trains up hills; this
      is related to weight and elevation, not to speed.

      Long, thin objects have high "Reynolds Numbers" which
      means that the amount of air drag is considerably lower
      than for short, fat objects.

      Mass of a train has no effect whatever on the amount
      of aerodynamic drag.

      Light, long, streamlined trains are the most efficient.
      Slower trains are more efficient than faster ones, all
      other things being equal.

      Again, the TGV double-decker gets good efficiency despite
      its very high speed.

      Regards,


      ----- ### -----
      J.H. Crawford Carfree Cities
      mailbox@... http://www.carfree.com
    • Matt Hohmeister
      Actually, this brings up a question I ve been wondering for some time. In an era of dwindling oil supplies, are we better off with jets or ships? 747 or QM2?
      Message 2 of 18 , Jun 17, 2007
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        Actually, this brings up a question I've been wondering for some time. In an era of dwindling
        oil supplies, are we better off with jets or ships? 747 or QM2? Or is there another solution?
        Anybody?

        > "The obvious replacements for planes are scarcely better. Fast passenger ships appear to
        be even worse for the environment than jets. ... [Paragraph] Nor are ultra-high-speed trains
        the answer. Though trains traveling at normal speeds have much lower carbon emissions
        than airplanes, Professor Roger Kemp of Lancaster University shows that energy consumption
        rises dramatically at speeds above 125 miles per hour. Increasing the speed from 140 to 220
        mph almost doubles the amount of fuel burned. If the trains are powered by electricity, and if
        that electricity is produced by plants burning fossil fuels, they cause more CO2 emissions
        than planes. Running trains on renewable electricity is certainly possible, but this faces
        problems: Trains must run on time, and that means there is little room for 'demand
        management,' which means reducing the electricity load in response to fluctuations in
        supply. In all transport systems, high performance is incompatible with low consumption.
        The faster you go, the more energy you need."
      • Richard Risemberg
        ... Ships do not have to be powered by oil or coal. Highly refined sailing vessels with solar auxiliary power for days of calms and for harbor maneuvering can
        Message 3 of 18 , Jun 17, 2007
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          On Jun 17, 2007, at 8:40 PM, Matt Hohmeister wrote:

          > Actually, this brings up a question I've been wondering for some
          > time. In an era of dwindling
          > oil supplies, are we better off with jets or ships? 747 or QM2? Or
          > is there another solution?
          > Anybody?
          >
          Ships do not have to be powered by oil or coal. Highly refined
          sailing vessels with solar auxiliary power for days of calms and for
          harbor maneuvering can move considerable tonnage and numbers of
          passengers. However, it is obvious that if we are serious about
          sustainability, we will have to accept that international trade and
          travel will be slower and more expensive. (Although someone, upon my
          telling them this, suggested that sail transport labor costs could be
          lowered by using crews of slaves...I hope they were kidding.)

          And no, I don't think nuclear-powered ships are the answer!

          http://tinyurl.com/25u5bt

          Rick
          --
          Richard Risemberg
          http://www.bicyclefixation.com
          http://www.newcolonist.com
          http://www.rickrise.com
        • dawie_coetzee
          Localization. ...it is obvious that if we are serious about sustainability, we will have to accept that international trade and travel will be slower and more
          Message 4 of 18 , Jun 18, 2007
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            Localization.

            "...it is obvious that if we are serious about sustainability, we
            will have to accept that international trade and travel will be
            slower and more expensive."

            Precisely. I know Joel Crawford takes a somewhat contrary position in
            his book, but I'm a firm localist. Pedestrian cities and localized
            economies are perfect for each other. Indeed, the one only comes to
            full fruition in the context of the other.

            -Dawie



            --- In carfree_cities@yahoogroups.com, Richard Risemberg
            <rickrise@...> wrote:
            >
            > On Jun 17, 2007, at 8:40 PM, Matt Hohmeister wrote:
            >
            > > Actually, this brings up a question I've been wondering for some
            > > time. In an era of dwindling
            > > oil supplies, are we better off with jets or ships? 747 or QM2?
            Or
            > > is there another solution?
            > > Anybody?
            > >
            > Ships do not have to be powered by oil or coal. Highly refined
            > sailing vessels with solar auxiliary power for days of calms and
            for
            > harbor maneuvering can move considerable tonnage and numbers of
            > passengers. However, it is obvious that if we are serious about
            > sustainability, we will have to accept that international trade
            and
            > travel will be slower and more expensive. (Although someone, upon
            my
            > telling them this, suggested that sail transport labor costs could
            be
            > lowered by using crews of slaves...I hope they were kidding.)
            >
            > And no, I don't think nuclear-powered ships are the answer!
            >
            > http://tinyurl.com/25u5bt
            >
            > Rick
            > --
            > Richard Risemberg
            > http://www.bicyclefixation.com
            > http://www.newcolonist.com
            > http://www.rickrise.com
            >
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