Cooling the Tube

Dealing with the heat on board the trains of London’s nearly 150-year-old Underground system has been a problem, especially in summer. The problem is that heat generated by conventional air-conditioning has to go somewhere.

Transport for London is working on multiple solutions, including improving existing ventilation shafts; tapping into underground aquifers to create water-based heat-exchange systems, and “hydro cooling,” using ice reservoirs and fan units.

As the infrastructure work continues, air-conditioned trains will be added to the system. The first cars, planned for the Circle, Hammersmith & City and Metropolitan lines, should arrive in January 2010.