At least 13 people are dead after a train transporting liquefied petroleum gas derailed and exploded in northern Italy.At least 36 other people have been seriously injured. Some 15 are in a critical condition. Most of the victims were in nearby houses. The accident happened near the train station in the Tuscan seaside town of Viareggio, about 350 kilometres north of Rome. Firefighters battled overnight to contain blazes started by at least three explosions.