As London heats up for another week of temperatures topping 30C, staying cool on commutes across the capital has become a mission for many.
Although those travelling on the Elizabeth line, London Overground and London Trams can enjoy fully air-conditioned carriages, most London Underground lines do not offer the same luxury.
Of the 11 main Tube lines, only four sub-surface lines feature air conditioning – the Circle Line, District line, Hammersmith & City line and the Metropolitan line.
More than 190 Tube trains, covering around 40 per cent of the Underground network, are now air-conditioned.
According to a 2025 FOI request to Transport for London (TfL): “The entire London Underground S8 stock, introduced between 2010 and 2013 operating on the Metropolitan line, as well as S7 stock serving the District, Circle, and Hammersmith & City lines, introduced between 2012 and 2017, are fitted with air conditioning throughout”.
The deep Tube lines – the Central, Northern, Victoria, Jubilee, and Bakerloo line – that make up 60 per cent of the network do not have air conditioning.
During June’s record-breaking heatwave, temperatures on the London Underground rail network reached almost 40C.
Readings taken by The Independent on London Underground carriages showed highs of 39.4C, recorded on the Central line – one of the capital’s busiest lines.
On the Central line, the 1992, 1995, 1996 and 2009 Tube Stocks do, however, have full air conditioning units installed in the driver’s cab to “improve working conditions for train operators”.
As of 2026, the Waterloo & City line is the only deep Tube fleet operating without cooling systems in the driver’s cab.
According to TfL, station cooling systems have been introduced to older parts of the Tube network, which have fewer ventilation shafts to help cool passengers.
New trains being introduced on the Piccadilly line later this year will have air conditioning in a first for deep Tube trains.
At present, the London Underground has not rolled out a new air-conditioned train since June 2017 – more than nine years.
Lilli Matson, chief safety, health and environment officer at TfL, said of London’s first-ever Heat Plan: “This report highlights the increasing risks that extreme heat poses across London, including to critical infrastructure such as transport. The ongoing heatwave has underlined the importance of preparing for such conditions and their real-world impact on customers, staff and the transport network.
“We are working with other agencies, including Network Rail, the Greater London Authority and others to develop a coordinated approach and manage the adverse impact of higher temperatures on our network, from track and road surface resilience to customer comfort and staff safety.”
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