Re: Evacuated Tube Transport

TomB wrote:

>2. Aren't hyperspeed trains also a big danger in
>terms of sabotage etc - as you have to secure
>their tracks too? Things like the TGV etc?

Sure, they are. But they only move at two-three *hundred* mph, whereas
the 
long-distance ETT capsules are supposed to move at four *thousand*
mph... 
from a kinetic-energy point of view that's a rather significant
difference. 
 From a braking-distance point of view too, at least if you assume the
same 
emergency deceleration for both vehicles (limited more by what the 
passengers/cargo can endure than by what the vehicle itself can survive)
:-/

>4. It has traditionally been far more efficient to move mass by rail
than 
>by truck or plane (by a
>long shot) - and this method looks even more energy efficient.

In addition to KHR's comments, you forgot one very important factor:
rail 
is "far more" efficient *iff* it goes *all the way to the final 
destination*. If you need to use a truck even a short way of the
distance 
(ie., to and from the railway terminals), the efficiency of the combined

rail-truck system drops very fast - which is one of the major reasons
why 
long-distance trucking is common even on routes where there's a railway 
line available. In spite of the gains from container systems, the
transfers 
from truck to train and from train to truck often cost you more than you

gain by using railway for the vast majority of the distance :-(

Side note to Ryan: Transporting tanks by train from Fort Hood to
Savannah 
harbour is a good example of this: the railway tracks do stretch all the

way from Fort Hood itself to the quays in Savannah, so it is easier to
use 
them than to use the tank transporters. If the tanks need to move any
real 
distance away from the railway line, you immediately need those 
transporters again (or you need to replace the pavement of every road
you 
drive the tanks on <g>)... which means that you need to get those 
transporters and their drivers to whereever it is they are to pick the 
tanks up...

>If your concern isn't the danger to the apparatus, but the cost
efficiency 
>of the
>system, this system may move KGs (and conventional rail definitely
does) 
>far cheaper
>across continental distances than your air-net.

Conventional rail *today* is far cheaper than the air net mainly because

the railways were built half a century or more ago. For the most part,
the 
investment has already been paid off.

However, if you compare the cost efficiency of a *new* long-distance 
railway line to that of using aircraft (and building a new landing strip
at 
either end of the route) it'll take quite a long time before the railway

beats the aircraft, simply because the initial investment is so much
larger 
for the railway than for the two airports.

(This is a cause of much teeth-gnashing amongst the local Greenies, BTW
- 
they love trains and hate all other modes of transport, and can't 
understand why the railways (particularly the new ones!) don't show a 
profit in spite of being heavily subsidised whereas truck and air
transport 
companies do fairly well... The distances involved here is the entire 
length of Sweden, which IIRC corresponds roughly to the distance 
Vancouver-Los Angeles. Not quite "continental" distances, but fairly 
respectable nonetheless.)

>I'm not saying this is viable any more than a space elevator is (both
are 
>contestible points).

I'd actually rate the beanstalk as more viable than the ETT :-/ Much
easier 
to guard (>99.9% of the approaches to it are through open air/space,
which 
is quite easy to keep under surveillance compared to a extensive network
on 
the ground), and a much less complex technical system too <g>

Later,

Oerjan
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
-Hen3ry