Re: Brief trip report MEL-CBR-MEL and thoughts on 737 vs A320 cabins.

[matthew@mail.usyd.edu.au (Matthew Geier)]

In article <397D35F8.A5CDCBF0@videotron.ca>,
JF Mezei  <jfmezei.spamnot@videotron.ca> wrote:
>James C wrote:
>
>But the TGV does not (and cannot) travel at high speeds on tradictional
>tracks. For one thing, a different power system is used, and the tracks a=
>re
>absolutely incapable of high speed.

 Not strictly true. More than the LGV tracks are 25K AC energised, and
France may have already have some 25K AC in place before the TGVs were
built. Much 'conventional' track is now 25K AC, with large numbers of
dual (and triple and quad) voltage locomotives in use, on both Freight
and passenger trains.

>
>Note that while high speed tracks are of the same gauge as traditional tr=
>acks,
>there are quite a few differences. They are built to much tighter toleran=
>ces,
>switches are built very differently to allow high speed travel,

 Shallow angle and 'movable frogs'. Queensland use them all the time. The
Tilt-Train can enter a loop at 140km/hr in places. (And thats a 'conventional'
mixed traffic line.

>are fenced all the way. The electric wires (cat=E9naires in french) are b=
>uild
>differently on the high speed line (different voltage, different tension =
>on
>the line etc).

 Voltage is the same as the 'new' parts of france. The geometry of the line
has to be the same for pantograph compatablity. Nothing stops a conventional
train from running on the LGV, except the cab signals and axle load.

>> SNCF also table a few freight trains on LGV at night besides maintenanc=
>e,
>
>Not freight trains in the north american sense. The whole point of having=
>
>tracks capable of high speed is to forbit freight traisn to travel on the=
>m
>because heavty freight trains damage the tracks.

 But a 'light' freight train can. All down to axle load and grades.

> Also, remember that
>traditional electric locomotives won't work on the TGV high speed lines
>because of different voltages used.

 Probably all currently in service SNCF electric locomotives are dual (or
more) voltage. What keeps them off the LGV high speed lines is axle load
and the lack of suitable cab signals. There may be some passenger/express
freight locomotives fitted with appropiate cab signals.
 Its a design constraint. The Germans built their first dedicated high
speed line to a standard that could take 25 tonne axle load freight. At
very high cost.

>One of the big accomplishements of the TGV was not the tracks, not the mo=
>tors,
>but the ability to transfer vast enough power from the cateraries to the
>pantographs to drive the train at high speed (and make that transfer work=
> at
>high speed).

 Power to weight ratio (22.4hp/tonne for the orginal TGV), and keeping 
the pan on the wire. Hence a TGV only raises one pantograph when running
under AC overhead to lessen the scope of the problem and has a high 
voltage cable running the lenght of the train to feed the rear power car.
The germans managed a better pantograph and the ICE runs with 2 raised.

 Note that the enormous power (10kW) is supplied through a few 10s of mm
of graphite contact bar....

 TGV trains also run at 200Km/hr on 'conventional' lines. Our XPT manages
only 160Km/hr, and then only on very short sections. Queensland is doing
better, i've ridden their tilt-train at 160km/hr over quite some distance,
and its not the tilt mechanisim that gives QR's train it's speed, its raw
power, and better track maintence. The tilt just means it takes curves faster...

>Is there the commitment and money to build a truly high speed rail line i=
>n
>Australia ? =

 Doesn't seem to be any shortage for a 2nd Sydney airport. An Airport that
the Government will pay for. Its a private company that proposed the 
high speed railway between Sydney and Melbourne. Are there a line of
people wanting to build and pay for a 2nd Sydney airport ?

 What they want - the same sort of tax concessions that CityLink got in
return for builting those tollways in Melbourne....