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63Re: [carfree_cities] Ranking US cities

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  • J.H. Crawford
    Apr 10, 2000
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      >> >Are the trolley buses you have in mind electric buses attached to power and
      >> >ground lines?
      >> There are positive and negative wires, but there is no ground that I know
      >> of.

      In the case of trolleys, there's one overhead "hot" conductor. The
      rails serve as the return path (at ground potential, of course).

      >Negative would do it. Path for the current. I was trying to get a fix on how it
      >worked. The trolleys could be grounded to the metal rails, but an electric bus on
      >rubber tires would have to be worked another way.

      Yes, two conductors are always required, and the amount of
      hardware that has to be installed up in the air is quite
      considerable. Also, it is quite common for one (or both!)
      trolley poles to come off the wire, which results in a
      delay while the driver tries to get the pole back on the
      wire. This sometimes takes a fair bit of time.

      >I find the use of trolley buses attractive because it would be relatively cheap to
      >string the cables, the road is already there.

      On the other hand, the cost for the overhead wires is more
      than double that for a trolley because of the complication
      of wires having to cross where routes join and diverge.

      >Several varieties of electric motor have already been put into service. The
      >problem is storage of power, but if that came off a line, problem solved.

      As far as I am aware, no in-service system has used storage
      (there are some tests with flywheels and batteries, I belive).
      Fuel cells would solve most of the problem, and some fuel-cell
      buses are under test.

      >Parts and repair for trolley buses would be available nearly everywhere. If one
      >needed major repair, it could be taken offline and towed.

      These buses are highly reliable. The main components are
      so long-lived that they are often set under a new coach
      body after 20 or so years.

      >I am ready to be corrected in this, the bikers in the group may jump all
      >over me for this, but it seems that a lane devoted to the exclusive use of bicycles
      >and trolley buses might be helpful. If the lane serviced nothing but bikes and
      >regular predictable buses, it would be a lot safer than sharing the road with

      My philosophy is this:

      Allocate space first to public transport (a la Zurich), so
      there are never any traffic-related delals.

      Make sure bikes get their own space (the speed differentials
      mean that the two kinds of traffic do not mix well).

      What's left over can go to the cars.


      J.H. Crawford _Carfree Cities_
      postmaster@... http://www.carfree.com
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