London Daily

Focus on the big picture.
Thursday, Sep 18, 2025

Why do Britain’s roads melt and its rails buckle in heat?

Why do Britain’s roads melt and its rails buckle in heat?

Some countries have designed their transport infrastructure for wider extremes of weather – but that comes at a cost

Extreme temperatures have led to widespread problems and disruption on Britain’s railways, with trains running at slow speeds and mainlines closed. Airport runways and some roads have also shown they can be susceptible to heat.


Railways


Steel rails expand and tend to buckle in the heat – whatever the climate. According to Network Rail, railways worldwide are designed to operate within a 45C (113F) range, according to the local conditions. In the UK, steel rails are “pre-stressed” to summer temperatures of 27C, whereas in countries with hotter climates, rails are pre-stressed to higher temperatures.

Sleepers and ballast must keep the rails in place in the British winter and summer. When the temperature hits 40C, rails can reach 60C and expand and buckle. A train travelling fast over rails can hasten that process through the heat caused by friction, and could be in more danger should buckling occur – hence the widespread speed restrictions.

The overhead wires on electrified routes also expand and sag in the heat, and contract in cold weather. Engineers have solutions, with the tension automatically mitigated by a pulley system. But eventually the counterweights hit the ground and wires sag – making them more likely to be tangled in a pantograph, the device on top of the train that draws power from the lines.


Roads


Motorways and strategic roads are built with modified asphalt surfaces that – so far – should not start melting, being resilient past 60C, or an equivalent air temperature of 40C, according to National Highways. However, basic asphalt materials used on local roads – the vast majority – can start to soften at temperatures of 50C. At that point, Prof Xiangming Zhou, the head of civil and environmental engineering at Brunel University, says: “The road can get soft and greasy, and it is difficult for cars to brake.” This is why councils have put gritting lorries, more usually employed in icy weather, on standby to coat roads in sand and dust. Tarmac and asphalt are cheaper and less abrasive to tyres than some materials, he says, but as they are black they tend to heat more quickly in baking sun.

About 4% of Britain’s roads are built from concrete, which is more popular abroad for highways and motorways and can be more resilient, but is not immune to problems of extreme temperatures, as the closure of the A14 shows. The dual carriageway near Cambridge had been built with asphalt over old concrete slabs that expanded and buckled in the heat, creating a bump sufficient to close the road overnight for emergency repairs.

Rick Green, the chair of the Asphalt Industry Alliance, says that for a road to cope with all temperatures is “a significant challenge for design engineers”. In extremely high temperatures the surface “doesn’t melt, but the bitumen in it can soften”, “heightening the risk of deformation”.

Airport runways


Again, some can be concrete – but Luton’s asphalt was the problem once temperatures soared into the mid-30s, says Zhou. In the airport’s words, “high surface temperatures caused a small section to lift” – a buckle in the runway that engineers fixed within hours, but that still caused major disruption to passengers. Whereas local roads are often shaded by trees and houses, runways are fully exposed and under further heat stress from aircraft landing and taking off. Repairs and maintenance are frequent.

Heathrow, which was even hotter than Luton on Monday, also had a runway issue last week, when overnight repair work did not finish in time for planes to land. However, it has two runways and was not forced to stop operations.


So what is the solution?


Network Rail is already spending hundreds of millions of pounds annually on climate change mitigation. Most of it, however, is to counteract erosion or damage through rainfall or storms. Future infrastructure could be gauged to a warmer climate – but then it could be more prone to failure and cracking in cold winter weather when rails contract. Some track materials, such as concrete sleepers, are more resilient at broader ranges of temperature and conditions – and significantly more expensive.

Rails are already painted white in critical spots to combat heat. Countries with extremes of weather carry out much wider seasonal adjustments to track, which is time-consuming and costly. Air-conditioning was not a standard feature of older trains still running. Resilience will become an economic and political choice – and it may be that a few days of outages for heat each year is seen as preferable to the bill for modifications.

Newsletter

Related Articles

0:00
0:00
Close
US Tech Giants Pledge Billions to UK AI Infrastructure Following Starmer's Call
Saudi Arabia cracks down on music ‘lounges’ after conservative backlash
DeepMind and OpenAI Achieve Gold at ‘Coding Olympics’ in AI Milestone
SEC Allows Public Companies to Block Investors from Class-Action Lawsuits
Saudi Arabia Signs ‘Strategic Mutual Defence’ Pact with Pakistan, Marking First Arab State to Gain Indirect Access to Nuclear Strike Capabilities in the Region
Federal Reserve Cuts Rates by Quarter Point and Signals More to Come
Effective and Impressive Generation Z Protest: Images from the Riots in Nepal
European manufacturers against ban on polluting cars: "The industry may collapse"
Sam Altman sells the 'Wedding Estate' in Hawaii for 49 million dollars
Trump: Cancel quarterly company reports and settle for reporting once every six months
Turkish car manufacturer Togg Enters German Market with 5-Star Electric Sedan and SUV to Challenge European EV Brands
US Launches New Pilot Program to Accelerate eVTOL Air Taxi Deployment
Christian Brueckner Released from German Prison after Serving Unrelated Sentence
World’s Longest Direct Flight China Eastern to Launch 29-Hour Shanghai–Buenos Aires Direct Flight via Auckland in December
New OpenAI Study Finds Majority of ChatGPT Use Is Personal, Not Professional
Hong Kong Industry Group Calls for HK$20 Billion Support Fund to Ease Property Market Stress
Joe Biden’s Post-Presidency Speaking Fees Face Weak Demand amid Corporate Reluctance
Charlie Kirk's murder will break the left's hateful cancel tactics
Kash Patel erupts at ‘buffoon’ Sen. Adam Schiff over Russiagate: ‘You are the biggest fraud’
Homeland Security says Emmy speech ‘fanning the flames of hatred’ after Einbinder’s ‘F— ICE’ remark
Charlie Kirk’s Alleged Assassin Tyler Robinson Faces Death Penalty as Charges Formally Announced
Actor, director, environmentalist Robert Redford dies at 89
The conservative right spreads westward: a huge achievement for 'Alternative for Germany' in local elections
JD Vance Says There Is “No Unity” with Those Who Celebrate Charlie Kirk’s Killing, and he is right!
Trump sues the 'New York Times' for an astronomical sum of 15 billion dollars
Florida Hospital Welcomes Its Largest-Ever Baby: Annan, Nearly Fourteen Pounds at Birth
U.S. and Britain Poised to Finalize Over $10 Billion in High-Tech, Nuclear and Defense Deals During Trump State Visit
China Finds Nvidia Violated Antitrust Laws in Mellanox Deal, Deepens Trade Tensions with US
US Air Force Begins Modifications on Qatar-Donated Jet Amid Plans to Use It as Air Force One
Pope Leo Warns of Societal Crisis Over Mega-CEO Pay, Citing Tesla’s Proposed Trillion-Dollar Package
Poland Green-Lights NATO Deployment in Response to Major Russian Drone Incursion
Elon Musk Retakes Lead as World’s Richest After Brief Ellison Surge
U.S. and China Agree on Framework to Shift TikTok to American Ownership
London Daily Podcast: London Massive Pro Democracy Rally, Musk Support, UK Economic Data and Premier League Results Mark Eventful Weekend
This Week in AI: Meta’s Superintelligence Push, xAI’s Ten Billion-Dollar Raise, Genesis AI’s Robotics Ambitions, Microsoft Restructuring, Amazon’s Million-Robot Milestone, and Google’s AlphaGenome Update
Le Pen Tightens the Pressure on Macron as France Edges Toward Political Breakdown
Musk calls for new UK government at huge pro-democracy rally in London, but Britons have been brainwashed to obey instead of fighting for their human rights
Elon Musk responds to post calling for the murder of Erika Kirk, widow of Charlie Kirk: 'Either we fight back or they will kill us'
Czech Republic signs €1.34 billion contract for Leopard 2A8 main battle tanks with delivery from 2028
USA: Office Depot Employees Refused to Print Poster in Memory of Charlie Kirk – and Were Fired
Proposed U.S. Bill Would Allow Civil Suits Against Judges Who Release Repeat Violent Offenders
Penske Media Sues Google Over “AI Overviews,” Claiming It Uses Journalism Without Consent and Destroys Traffic
Indian Student Engineers Propose “Project REBIRTH” to Protect Aircraft from Crashes Using AI, Airbags and Smart Materials
French Debt Downgrade Piles Pressure on Macron’s New Prime Minister
US and UK Near Tech, Nuclear and Whisky Deals Ahead of Trump Trip
One in Three Europeans Now Uses TikTok, According to the Chinese Tech Giant
Could AI Nursing Robots Help Healthcare Staffing Shortages?
NATO Deploys ‘Eastern Sentry’ After Russian Drones Violate Polish Airspace
Anesthesiologist Left Operation Mid-Surgery to Have Sex with Nurse
Tens of Thousands of Young Chinese Get Up Every Morning and Go to Work Where They Do Nothing
×