According to this BBC Blog, the reason our trains are more disrupted when it snows is because they use the "third rail system". This makes interesting reading but unless the train system is improved, we are likely to continue to suffer delays when it snows and freezes.
From the link above:
"In south London the companies like Southern Railway, Southeastern and South West Trains have to operate using the "third rail system".
That is, the electricity is transmitted to the train using an electrified third rail that the train picks up through a bit of metal called a shoe.
So, while Network Rail have been running "ghost trains" (empty trains) and de-icing trains through the night there comes a point when it doesn't help.
When the snow and ice hits, if the conductor third rail is cold as soon as snow hits it, it freezes. That means there's an insulating layer of ice between the shoe and the rail.
Southeastern have told me the trains automatically shut down to prevent "arcing" of electricity - that could damage electrics and is potentially dangerous."
