On Sat, 9 Aug 2008, Edward Cowling London UK wrote:

In message , John Rowland
writes
Edward Cowling London UK wrote:
After another grim morning on Friday, I wonder why the ventilation on
the Victoria Line is so bad ? If you change to the Piccadilly at
Finsbury Park it's like entering a different world. So if the Picc
Line can stay reasonably fresh why can't the Vic Line ? Even with
the trains at full hurtle little air seems to move about the carriage.

The Victoria Line is completely underground, except for the depot. The Picc
has several open air sections.

Which makes it sound unlikely the refurb and new trains will help.

They should do. Firstly, they'll have regenerative braking, which means
less of the train's kinetic energy will be turned into heat, so the
tunnels won't get as hot in the first place. Secondly, i understand
they've been designed with better ventilation: what matters is the
temperature on board the train, and this has got as much to do with
airflow between the train and tunnel as with the temperature in the tunnel
itself. I posted a link to a paper on some research about this a few weeks
ago; i don't have it to hand, but i seem to remember that better
ventilation could buy a few degrees of coolness.

tom

--
What we learn about is not nature itself, but nature exposed to our
methods of questioning. -- Werner Heisenberg