Re: [carfree_cities] Bargain-basement underground transport?
- Most Metros are built using cut-and-cover these days, I think.
The system you envision would not have the capacity of a metro. Even
LA's Metro Red Line (the other lines are surface light rail) can carry
800-1000 passengers per train, and rush hour trains are pretty full.
New York's and some of Tokyo's can carry more, with headways as low as 3
minutes sometimes. Small stations limit train size, so you just end up
with an underground bus--in which case you may as well just have busways.
My 2 cents.
Erik Rauch wrote:
> I don't know much about transportation engineering, but pondering why a--
> metro is expensive brought to mind a possible alternative.
> The great advantage of the metro is its grade-separated, dedicated right
> of way. But tunnelling and underground stations, though cheaper in a new
> development than in an existing city, are still expensive. In building a
> new carfree area where money is scarce, could one simply dig a shallow,
> cut-and-cover tunnel and run self-guided vehicles through it, of the type
> described in the January 2004 Carfree Times? At its most basic, the tunnel
> could be nothing more than a trench covered by grates. The small size of
> the vehicles would require only a shallow tunnel: the vehicles can be only
> about 2 meters high. Stops could simply be pits with stairs surrounded by
> fencing. Crossing lines would need to be handled, but with automated
> guidance, it should be possible to do this at the same grade, avoiding the
> need for tunnelling under a trench. This idea has some things in common
> with a people mover, but without the drawbacks of elevated structures.
> Though not as nice as a full-blown metro, such a system, if feasible,
> would have some of the most important advantages that the metro has over
> surface transport - even trams.
> I wonder if such a system would be feasible and indeed be significantly
> cheaper than a metro.
"I believe that every right implies a responsibility; every opportunity,
an obligation; every possession, a duty."
John D. Rockefeller, Jr.
- Richard Risemberg said:
>Most Metros are built using cut-and-cover these days, I think.Not always; here in Amsterdam, world capital of soupy soils, they
are going to bore the new metro deep underground using a tunnel
boring machine. Metros close to the surface probably are built
mostly with cut-and-cover, but many have to be deep in order to
clear existing underground works.
>The system you envision would not have the capacity of a metro. EvenNot necessarily; the EuroTram is nearly as wide as a metro car and
>LA's Metro Red Line (the other lines are surface light rail) can carry
>800-1000 passengers per train, and rush hour trains are pretty full.
>New York's and some of Tokyo's can carry more, with headways as low as 3
>minutes sometimes. Small stations limit train size, so you just end up
>with an underground bus--in which case you may as well just have busways.
can be lengthened as needed to reach about the same capacity for a
given length of boarding platform/train. It has to do more with the
designed capacity than the particular mode.
And, of course, any system in a tunnel avoids street traffic.
-- ### --
J.H. Crawford Carfree Cities
- Hello all
In response to discussion about energy provision for a car free city Jim
'work on the city's infrastructure, particularly the transportation
so as not to waste so much energy in the first place'
I agree with this and it should be a central concept in 'green' design.
simple design features such as a rise into a metro station and a fall out of
it save energy on deceleration and acceleration and can easily be
incorporated as the infrastructure is put in place.
Get some great ideas here for your sweetheart on Valentine's Day - and
- I had to link to this...
- --- In email@example.com, Jym Dyer <jym@e...> wrote:
> > I mean, how would you power a carfree city? 100 percentHow is this off-topic? You gotta power that huge rail system with
> > windmills? It'd never work. Tuck in a pair of nuclear plants
> > out in the industrial districts and now you're talking! :)
> =v= I'm not going to rehash an off-topic nuclear power debate
> on this list.
something, right? Have to keep the lights on in all those high-
density housing units. Got to keep the economic engine ticking over
reliably, right? Magical pixie-dust power won't cut it.
Also, to be honest, cars use a fairly small percentage of the USA's
energy. A modern industrialized economy is a hungry mother, and
unless we want to look at radical changes in the economy even beyond
ditching the automobile, we're going to have to feed the economy lots
Here, check this .pdf:
That paper shows that in 2000, the USA consumed a total of 98.5
Quadrillion BTU's of primary energy. Of that, only 26.6 Quads was
used for transportation, and even carfree cities won't displace all
> Anything I might have to say on the matter wasSo, you're basicaly stuck in the past and have no defense for your
> said 30 years ago by Amory Lovins, and about the massive costs
> of decommissioning in particular, 20 years ago by Karl Hess.
baseless comments? :)
How about a more up-to-date look at things:
According to that paper, $22.5 billion has been set aside already to
decommission the US nuclear fleet, with many more billions to come.
This is money charged to you, me, and everybody else who uses nuclear
electricity, and is not charged to the government.
> =v= As for what I'd so, it's the same thing I've been sayingName said sources, please.
> for the four years I've been on this list: work on the city's
> infrastructure, particularly the transportation infrastructure,
> so as not to waste so much energy in the first place. That way
> they can be powered largely, if not totally, from clean energy
Windmills? Excellent powersource, except that wind has low capacity
factors and is intermittant.
Hydro? Wonderful source of power, except it has stringent siting
issues, and droughts can be worrisome.
Solar? Passive solar thermal is on the ragged edge of viabillity,
photovoltaic is completely out of the question.
Natural gas? Seen the price of gas lately? :)
> Ads below? Just ignore 'em.