"Alex Terrell" wrote in message
om...
"Bob" wrote in message
...
"Alex Terrell" wrote in message
om...
The specialised 186mph trains are due to start running from stations
in
Kent
to London along the Channel Tunnel Rail Link (CTRL), but ministers
are
still
arguing over which rolling stock to order.

Over engineered trains again. Would it not be eaiser to use the line
at 160mph and add 5 minutes to the London Paris journey time?


It would be even easier to run it at 90mph and use MK1 EMUs (lots of
them
going spare now), but that would be missing the point of the line,
wouldn't
it?
Slam door?

I suspect train cost is proportional to kinetic energy, i.e rises with
the square of the velocity. So there will be an optimum speed.

It's about 70 miles St Pancras to the tunnel, so:

180 mph = 23 min
160 mph = 26 min
150 mph = 28 min
140 mph = 30 min
90 mph = 47 min

Trains running at 140 mph adds only 5 min, but makes the commuter
problem much, much easier.

(Velocities are max, I know average speeds will be less, but the logic
is the same).

In my world, 30-23 is 7 not 5.

Anyway, the point of the line is to cut as much as possible off the journey
time between London and Paris / Brussels. Running trains at 186mph is the
plan - your commuter trains at 140mph would get in the way.

Since the technology exists for 186mph running, why not just build the damn
trains instead of messing things up with a stupid fudge. Your kind of
thinking is why things always turn to crap in this country.