Britons across the country have been battling sweltering temperatures over 30C as the UK’s third heatwave of the year continues.Some are taking desperate measures seeking refuge in hotels, booking a room only to catch a break in the air con. But in a country that largely lacks the infrastructure to cope with extreme heat, which trains actually have air conditioning? The London Underground hasn’t introduced a new air-conditioned train for almost a decade, with the most recent being rolled out in June 2017.Around 190 Underground trains have air conditioning, but all of the air-conditioned trains operate on the shallow lines.The deep-level trains, like the Bakerloo and Piccadilly lines, make up the majority of the network but are yet to be kitted out with air con. Transport for London insists narrow Victorian-era tunnels leave little space to fit cooling equipment on the outside of carriages. However, fitting air conditioning isn’t impossible for the deeper lines, and the Piccadilly line is set to become the first to be fitted with air conditioning later this year. The new trains, built by Siemens, fit small, ultra-modern air conditioning units under the carriages.London TravelWatch told the FT the new trains – which won’t be ready until at least December when temperatures have already plummeted – ‘can’t come soon enough’. With limited air conditioned tubes to choose from, which trains in the UK are kitted out with it? Most of the London Underground doesn’t boast air conditioned carriages, but there are trains across the UK that doChiltern ExplorerSome newer Chiltern Railway trains have air conditioning, like the Chiltern Explorer fleet which launched in January.The trains operate between London and the West Midlands and feature automatic onboard air conditioning. The tech reacts to outdoor temperatures accordingly, making sure the carriage feels comfortable. South Western Railway South Western Railway operates its own fleet of trains, whilst also managing around 200 stations. ‘Most of our trains have air conditioning but it’s worth carrying a fan,’ its website reads.’If there are issues with a train’s air conditioning then our guards will let you know, and you may wish to consider moving to a different carriage.’The new Arterio trains are equipped with air conditioning and first launched in 2024.Avanti West Coast With trains operating on routes across the country, Avanti West Coast serves millions of passengers a year. All of its trains are equipped with air conditioning and the operator promises they all ‘receive regular maintenance to keep them in good functional condition’.It uses remote HVAC performance data to help fix any issues with the air con ‘before they become apparent in service’. ‘Should one of our conditioning units stop working, our on-board manager will do everything they can to move customers to an alternative coach with a functioning unit,’ the Avanti West Coast website reads. The Chiltern Explorer (pictured), which launched in January, has automated onboard air conditioning All of Avanti West Coast’s trains are equipped with the cooling technology, tooGreater Anglia trainsGreater Anglia has stations based in London, Cambridgeshire, Essex, Norfolk, Suffolk and Hertfordshire.All Greater Anglia trains have air conditioning as well as heating systems, so you can feel confident you won’t be struggling with the heat too much if travelling between London and the east of England. The air conditioning units circulate cold air every six to nine minutes. The Stadler-built trains have systems controlled automatically by the train. Great Western RailwayOperating services across London and to the west of England, Great Western Railway is one of the largest train companies in the country. All of its trains either have air conditioning or ventilation provided via extractor fans and hopper windows that are capable of being opened. The air conditioning technology combines fresh air intake with air in the saloon. This changes the air in the carriages completely multiple times each hour, according to its website. London North Eastern Railway LNER connects London to the north of the country and serves millions of passengers each year. Its trains boast a ventilation system that supplies the carriage with a continuous flow of fresh air. The company has also previously confirmed in a post on X that, ‘all of our trains have individual air conditioning units’. London North Eastern Railway trains have air conditioning ThameslinkAs for Thameslink, which operates across London, most of its trains feature air conditioning. ‘We’re also bringing in brand new air-conditioned trains on more of our routes over the next two years,’ the company states on its website. Elizabeth linePart of the Transport for London network, the Elizabeth line has fully air-conditioned carriages.The line first opened to passengers in May 2022.