Re: Traction (was Re: OT: Debian Mailinglist server slow?)
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On Wed, Sep 03, 2003 at 10:07:39AM +0100, Karsten M. Self wrote:
> More significantly though, for long
> trains, is the elimination of the stringlining problem. This is the
> result of having all your motive force at one end of a long line of
> cars, while drag is distributed through the train. On a long curve (or
> series of curves), the tendency is for the string to straighten out.
Well, modern setups allow you to have power in arbitrary locations
throughout the train. Extremely long trains through the rockies tend
to run 2 Dash-9s and a GP38-2 at the head of the train (or 3
Dash-9's), with another GP38-2 or Dash9 midway down, and usually a
Dash-9 picking up the rear. If you have a Windows box laying around,
Microsoft Train Sim has several scenarios running with power set up
like this as well if you wanted to try your hand at it. Controls are
synched between all power units automatically (iRL and in the game).
Interestingly enough, if you're in the north Willamette Valley, get
yourself to downtown or Northeast Portland and hop on the 8 NE 15th
Ave to Portland or the 8 JACKSON PARK to US-VA Hospital. This is a
very steep bus route, TriMet is starting to introduce diesel-electric
busses. On SW Campus Drive (which has about a 200 foot elevation gain
in it's single block), these puppies *fly* up the hill like it's flat,
while the diesel-hydraulic busses struggle up the hill in first gear
and do zero to 15 in about 20 seconds (pedal to the metal) pulling out
of a stop on that hill.
> Downsides of electrification are notably the cost of electrifying the
> RoW, and aquisition of stock.
Though this has incredable ROI on local passenger and interurban
lines. See also: Portland's MAX, Toronto's subway and infamous
"Vomit Comet" surface lines, and the New York Subway System.
Electrified trolley lines (you know, a bus with a pole going to an
overhead line) used to have a pretty good ROI as well, though I don't
think they do any more with the advent of fuel cell and
diesel-electric busses, which are starting to be adopted in cities
whose planners aren't retarded.
> Also, back in my intern days at SMUD, I recall that the city's light
> rail system operated in power blocks seperated (though not fully
> independent of) the city grid, largely because of the acceleration and
> deceleration power draws and surges.
I'm not sure anybody realised the warehouses (my high school was
Tektronix Warehouse #42 before it was a high school, Tektronix
remodeled it into a practically windowless high school...those
hallways had such loud acoustics that you could stand in the back of
the building by the cafeteria doors and speak in normal conversational
tones to someone standing in the front lobby on the other end of the
building) were getting affected by the trains.
- --
.''`. Paul Johnson <baloo@ursine.ca>
: :' :
`. `'` proud Debian admin and user
`- Debian - when you have better things to do than fix a system
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