First Air-Conditioned Tube Train Delivered

London's first air-conditioned train, part of a fleet that will eventually rumble along the Circle, District, Metropolitan, and Hammersmith & City lines, has been delivered to the Neasden depot for testing. The new S-stock trains, which we got a sneak preview of last year, will be introduced on the Metropolitan line from next year, and the fleet of 58 should be gliding smoothly from Amersham to Aldgate and all points inbetween by 2011. The Circle line will be the last to get the upgrade, by 2015. Tube cooling has long been a hot issue: a competition in 2003 calling for ideas had few credible entries, and TfL has resorted to less complex methods such as positioning giant fans in stations. Air-conditioned trains are a notable step forward, but a glance at the tube heat map reveals that the sweltering depths of the low-level lines are where things really heat up — and there's little chance of a cooling system down there.