wrote:
On Sat, 08 May 2021 10:40:53 +0100
Charles Ellson wrote:
On Sat, 8 May 2021 09:15:17 +0000 (UTC),
wrote:

Rubbish.

Rubbish yourself.
"one of the main reasons (and justifications) for having
PEDs is for ventilation although of course they do have the obvious
benefit of preventing people from falling onto the track."
https://www.whatdotheyknow.com/reque...m_screen_doors

No idea what that site is ,

It's the official site where Freedom Of Information (FOI) requests are
handled.

but clearly neither them nor you have ever
been on the tube. The piston effect of the train pulling and pushing air
through the tunnel provides plenty of ventilation into the station. In fact
the doors actually prevent a lot of that leaving some station platforms
uncomfortable on hot days IME when I worked at Canary Wharf particularly
London Bridge.


The piston effect of the trains pumps hot air around the tunnels from one
station to another, great.

If you visit very hot places like Singapore or Hong Kong you'll find that
almost every underground metro station has full-height platform edge doors
which completely isolate the air in the tunnels from the air in the
platforms. You can then have air-conditioned trains and platforms (both
nice and cool); as you step from train to platform or vv. you can feel a
layer of very hot tunnel air as you step through it (like those heaters
above shop doorways which used to be popular).

Used properly, it can be very effective.


Anna Noyd-Dryver