I can't think of an explaination for the widespread disruption that
/isn't/ ice-on-the-conductor rails - something like the national
grid being unable to supply sufficent current to LUL due to their
issues would have affected the victoria, circle and bakerloo too:
and they didn't report power supply problems.
What's a plausible alternative?
Problems with substations?
Aren't the substations on the deep lines just as exposed to the
weather as the substations on the surface lines?
Some may be, I think others are in shafts. But not all open lines were
affected, either. For example, the District line was fine. The closure of
the whole Met and Uxbridge branch of the Picc probably was a power supply
problem; the later problem on just the Amersham branch was more likely to
have been icing on the rails.
I doubt it was as simple as that. If it was just icing on conductor rails
why was Chiltern unable to run from Amersham to Marylebone?
Met train(s) stuck and blocking the track probably.
