With the UK just emerging from its hottest summer on record, London’s rail authorities are trying to adapt the capital city’s Victorian-era infrastructure, to keep commuters safe next time climate-driven heatwaves hit, including by introducing air conditioning to the ‘deep Tube’ for the first time.
London’s underground railway network – nicknamed the Tube – first opened in 1863 and is the oldest in the world. Partly because of its age, many of its lines are not air-conditioned, with platform temperatures averaging above 30 degrees Celsius in the summer, leaving passengers and staff faint, dehydrated and angry.
London’s two main rail authorities – Transport for London (TfL) and Network Rail – told Climate Home News they recognise the problems climate change is causing for their passengers. They said they are making efforts to adapt by increasing ventilation, installing some air conditioning and making station lifts more resilient to extreme heat.
Light-headed on the Tube
Andrea Jacobs spoke to Climate Home at Kingsbury station – where she often commutes on the Jubilee Line – about one hot journey a couple of years ago. “We were packed in there like sardines,” she said. “I was standing and I couldn’t move or breathe. Everyone was sweating… it was just too humid and I started panicking because I couldn’t breathe properly.”
“I had to get off at the next station, use my inhaler and sit on the platform for ten minutes. If I didn’t, I definitely would have passed out,” she said, adding that she is now more hesitant to get on busy trains and always carries one of the small handheld electric fans that are now a common sight in London during the summer.
The temperatures on crowded carriages are even hotter than on platforms, explained Mike Tipton, a physiology professor at Portsmouth University. The moisture that people produce makes the carriages humid, limiting fellow passengers’ ability to evaporate sweat and thereby cool their bodies.
When standing, this challenges peoples’ cardiovascular systems – made up of the heart and blood vessels – and can lead to light-headedness and fainting. This is particularly the case for those with heart problems, the pregnant or the elderly.
Lift failures and climate change
Older and disabled people are also badly affected – along with those travelling with small children or suitcases – when heat causes failures in the lifts at London’s train stations.
This is an increasing problem, Network Rail spokesman Chris Denham said, as “climate change means we are facing warmer hotter summers which put our lift estate under strain.”
The organisation, which manages railway stations and infrastructure across Britain, set up a working group on overheating two years ago.
Data on Network Rail’s lift breakdowns, obtained by Climate Home through a freedom of information request, shows the scale of the problem. On July 17, 2022 – the hottest day of that year – there were 17 lift breakdowns unrelated to wear and tear at Network Rail-run stations in London.
At several stations, more than one lift broke down on that same day, leaving many disabled people stranded and forcing passengers to carry prams and luggage up the stairs in the baking heat.
Denham explained that most of Network Rail’s lifts rely on hydraulic fluid, which works best within a limited temperature range. Above a certain heat, the lifts shut down to protect the system and minimise the risk of it failing between floors with passengers stuck inside, he said.
Network Rail is responding to climate change by improving ventilation and cooling to the lift systems and by “making sure that the next generation of hydraulic lifts are more resilient to hot weather”, he explained. These solutions are working to an extent, he added, but warned “they aren’t a silver bullet” because air conditioning is expensive and complex to install, and some machine rooms are too small for it.
“The frustrating thing,” he said, “is that accessible travel is booming, so more people than ever need those lifts. We have to do everything we can to keep them open.”
Air con on the Piccadilly Line
Nick Dent, director of customer operations at TfL – which manages the Tube – said he too is “working hard to ensure our transport services remain resilient in the face of more extreme and frequent hot weather events”.
He said that trains are being made more energy-efficient, which reduces the heat they generate. More efficient engines convert more energy into propelling the train forward, rather than losing it in the form of heat through braking, friction and engine inefficiencies.
Currently, only London’s shallower lines – like the Circle and the new Elizabeth Line – have air-conditioned trains.
The deeper lines – like the Central, Victoria and Northern – don’t, because the tunnels are too narrow and lack the ventilation needed to dissipate the extra heat the air-conditioning units would produce. The cramped tunnels also mean that air-conditioning units can’t go on the roof of the trains as they do in much of Europe, railway engineer and writer Gareth Dennis explained.
But according to TfL’s Dent, in 2026, air-conditioned trains will be introduced onto one of London’s deepest lines – the Piccadilly – as well as the above-ground Docklands Light Railway. The air-conditioning units will be fitted under the train. Dennis said this is now possible because air conditioners have become smaller and because of improvements in train and track design.
Other measures TfL is pursuing include adding industrial-sized fans at older stations that have less ventilation, trialling cooling panels at Knightsbridge station and better monitoring of track temperatures.
TfL’s limited budget
Dennis said that TfL’s ability to adapt to heatwaves is limited by its budget, which mainly comes from customers and the central government, and is “way lower than what other countries have in terms of capital investment”.
The Tube’s age and complexity is another challenge, he said, as “you’ve got layers and layers of 3D Swiss Cheese of tunnels and basements and infrastructure all twisting in and around each other”.
But he said there is hope. “We’ve got new trains and many new cooling projects. We want to harness that engineering knowledge and energy. We want to get people excited about making sure we deliver those at a larger scale, so that our experience on the Central line isn’t as miserable as it usually is.”
