On Tue, 1 Jul 2008, Tom Barry wrote:

According to TfL, the heating effect arises because of the incremental
heating and cooling caused by each passing train's energy consumption.
The frequency of trains means the cooling of the tunnel walls is that
little bit less than the heating, so over the years the ground heats up
because it never gets a long enough break between trains. This is
rather borne out by the original Bakerloo Line claim that it was an
nice, cool way to travel in the heat of the summer - it was decades
before the effect was realised.

This seems like an extraordinary proposition to me. Could you refer me to
any documents giving more details?

Presumably if you could shut the tube for a few years you could reverse
it, but I can spot a couple of problems with that idea.

Or do a one-week shutdown and blow cold, damp air through the tunnels.

tom

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