For a cooler journey by underground, just add ice under the seat

It may seem a rather basic solution to an age-old problem. But if it works, then millions of passengers on the London underground will hardly complain when it starts getting hot and sweaty on the tube.

In an effort to cool things down in the summer, the network is planning to put blocks of ice underneath the seats of trains.

The idea is not foolproof by any means. Unveiling the idea yesterday, experts conceded that the ice would melt fairly quickly as a result of heat radiated by commuters' backsides, which is why they are working on a refrigeration system to re-freeze the water.



Trials of the system will take place early next year as part of a £150m "hi-tech" push to make travelling on the tube network more comfortable by reducing the excessive build-up of heat in tunnels, trains and concourses.

Trains will be fitted with new refrigeration units that chill water to freezing point as they enter tunnels, where problems with overheating are the most severe. Once inside a tunnel, the trains' refrigerators will switch off, allowing the ice to melt.

Air pumped over the melting ice will be released through vents behind passengers' seats to cool the rest of the carriage, officials said. "In many ways, it's like taking a block of ice on board and letting it melt," said Kevin Payne, programme director of Cooling the Tube at London Underground.