"Michael Bell" wrote in message
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Michael Bell wrote:

There is an interesting article about heat (as experienced by
passengers) in the Tube in this week's New Scientist.


Michael Bell

The problem with on-train refrigeration is that it dumps the heat into
the tunnel, which get back into the train which....

A work-round discussed in this article is for on-train refrigeration
to make ice while the train is on the surface and allow it to melt
while in the tunnel. But not all routes have surface sections.

A truly radical idea might be to pipe on board at the terminus liquid
air (no need to separate it into oxygen and nitrogen) and evaporate it
in the tunnel. Disposal of the waste is not a problem!

Apart from the last idea, I think these are quite old, superseded
proposals. As I understand it now, the current active proposals a
1. Improve ventilation of deep Tube stations, to extract heat from the
system (already happening)
2. Fit airconditioning to new lightweight articulated Tube stocks which
have regen brakes and will produce less heat from their motors (hoped
for in the proposed replacement for 1972, 73 and 92 stocks).

One other idea was to use cool ground water being pumped out from
tunnels to cool the tunnel air mass, but I think this proved too
expensive.