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Blazes in train tunnels can be devastating—even more so if the train
carriages hold fuel-carrying vehicles. Henry Keith of London argues that all
vehicles entering Channel Tunnel trains, for example, should be moved past a
fire detector and temperature sensor before being loaded on (GB 2 320 971). Any
vehicle that shows a hot spot is diverted to a side lane. Cleared trucks are
loaded in modified freight wagons, with roller shutters at the side. At the
first whiff of smoke, the shutters drop, and the fire extinguishers operate
automatically.