I think he was referring to the S8 stock currently on the Hammersmith & City, Circle and Metropolitan lines (and being trialed on the District line https://twit

I think he was referring to the S8 stock currently on the Hammersmith & City, Circle and Metropolitan lines (and being trialed on the District line https://twitter.com/jamescun/status/516498515963695105 https://twitter.com/jamescun/status/516498515963695105) which have air-conditioning.