Trains of ice? Store the heat as water and run them through slowly overnight. Freeze again on the surface during the day. Edit: http://news.bbc.co.uk/1/hi/engl

Trains of ice? Store the heat as water and run them through slowly overnight. Freeze again on the surface during the day. Edit: http://news.bbc.co.uk/1/hi/england/london/5058362.stm http://news.bbc.co.uk/1/hi/england/london/5058362.stm