London is the coolest city on the planet and now we're getting the coolest trains too
The new trains are part of Transport for London's (TfL) Investment programme.
A mock-up of the new trains, which will serve around 40 per cent of the Tube network, will be on display at Euston Square Gardens for the public to view from Saturday 27 September to Thursday 2 October.
Passengers will benefit from air conditioning, walk-through carriages, CCTV coverage in each carriage and improved accessibility.
The Mayor of London, Boris Johnson, said: 'London is the coolest city on the planet and now we're getting the coolest trains too.
'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.
'As well as keeping passengers cooler the new trains feel far more spacious, boast the latest CCTV systems and have been designed to make life much easier for disabled passengers.
'When the full upgrade of our sub surface lines is complete, including the work improving signaling, capacity on these lines will be increased by over 45 per cent, which will mean less crowding and also mean we can cope with the continuing increase in passenger numbers.'
Peter Hendy, Transport for London Commissioner, said: 'The new air-conditioned trains are part of vital upgrade works which will transform the oldest and complex lines on the Tube network - the Circle, District, Hammersmith & City and the Metropolitan lines.
'When works are completed passengers will see faster, more reliable journeys and more trains per hour.
'The new air-conditioned trains will be common to all the Underground's sub-surface lines and will help us deliver a better service to passengers, with improved accessibility, more space and enhanced security.'