"Charlie Whitaker" wrote in message
news:charlie-
First, reduce the amount of train braking energy dissipated into deep
tunnels in the form of heat by upgrading as much of the rolling stock as
possible with regenerative brakes as opposed to rheostatic brakes.
Braking energy from rheostatic brakes accounts for a large proportion of
tunnel heating.


Regen braking has been tried previously on both the underground and other
railways. Where it has fallen down in the past is having somewhere for the
regenerated electricity to go and be used at the moment is it being
generated, i.e. as one train is braking for a station another needs to be
accelerating away.