"Piccadilly Pilot" wrote in message
...
"Marratxi"
I believe there is a solution, its a bit Heath-Robinson but consists of
a
large tanker wagon, filled with water, pulled behind each train. As the
train goes through the tunnel a very fine but copious spray of water is
pumped out behind the train. This will absorb heat from the air and
reduce
the temperature. I claim the prize !!!
Cheerz,
( © ) Baz

Hmmm, yes. But just a couple of points to dampen your euphoria (without
wishing to be a complete wet sponge).
What happens to all the water so sprayed?
Having pulled this tanker to the end of the line how does it get
transferred
to the rear of the train and refilled in time for the return journey?

1. The water gets pumped out along with all the other water which
accumulates in the tunnels.
2. The tanker is long and low so the driver can see over the top of it when
returning - there could be a tanker at each end of the train and a large
water-delivery pipe at each end of the journey, rather like some
water-powered funiculars are re-charged. I didn't say it was elegant but I
believe its simple, cheap and it would work - spray yourself with a mister
and see how well it cools you.
Cheerz,
Baz