The air-conditioned carriages will be in service from 2010
A model of an air-conditioned Tube train, due to be introduced on the Metropolitan Line in two years time, has been unveiled.
The new trains will be added to the sub-surface Circle, District and Hammersmith and City lines in 2011.
The £1.6bn fleet of 191 trains will have improved CCTV cameras, disabled access and walk-through carriages.
Unveiling the model, London Mayor Boris Johnson said passengers will be "cool as cucumbers" onboard the new trains.
Mr Johnson said: "After decades spent sweltering in tropical conditions on the Tube, in just two years' time Londoners on the sub-surface lines will be able to use the first of these superb trains.
"I can assure passengers who will use them that we hope rather than arriving at their destinations drenched in perspiration they will emerge cool as cucumbers and ready to enjoy all that the capital offers."
The trains felt "far more spacious" and were designed "to make life much easier for disabled passengers", he added.
David Waboso, the director of engineering at London Underground, said workers were examining ways to air-condition other "deep" Tube lines, such as the Northern and Piccadilly lines.
"The Tube network has many different challenges, so there's not one solution that fits all," he said.
The trains will be built by Bombardier Transportation in Derby.
The new design will be on display in Euston Square Gardens from Saturday until 2 October.
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