Trains in most of SE England run from a 660Vdc third rail and new trains all have electrical equipment under the floor. This is a recipe for complete network closure in extreme weather conditions.
http://news.bbc.co.uk/1/hi/england/8428097.stm
http://www.a1steam.com/index.php?opt...ews&Itemid=123
(Incidentally, it's so much easier to post on the Island than on the Zed but I did give it another try today).