"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?