Rahul SomvanshiA Greater Anglia train came off the tracks at Wickford station in Essex on Friday afternoon. About 40 people were on board. No one was hurt. The day before, a Southern train derailed near Lewes in East Sussex. Two passengers were seriously injured. Around 150 people were on that service.
Both incidents happened during the UK’s fifth heatwave of the summer. Network Rail’s safety director Martin Frobisher called the conditions “unprecedented hot and dry weather.” He said the railway faced “exceptional challenges.”
Steel rails expand in heat. Professor Xueyu Geng at the University of Warwick says a one-degree Celsius rise causes about 11 millimetres of expansion per kilometre of track. When rails have nowhere to expand, they buckle. A passing train can then push the buckled rail sideways, causing a derailment. This is called a track buckle.
Gareth Dennis, a railway engineer, said the chance of two similar derailments in the hottest part of the country within 24 hours without a common cause is “extremely low.” He believes track buckling is the likely factor in both cases.
Richard Bowker, former chair of the Strategic Rail Authority, said investigators will look at whether the ground beneath the tracks dried out. Clay soils in southeast England shrink during long dry spells. This can shift the track bed.
James MacCleary, Liberal Democrat MP for Lewes, said constituents had reported “bumpier” tracks for months. He linked it to sustained heatwaves.
Network Rail said it had taken proactive steps. These included monitoring track temperatures, imposing speed restrictions where needed, and scheduling track renewals around high temperatures. The Rail Accident Investigation Branch sent inspectors to both sites.
The Department for Transport said British railways “remain amongst the safest in the world” and that such incidents are “extremely rare.”
John Whitehurst, chief executive of Govia Thameslink Railway, praised four railway workers — the driver, an onboard supervisor, a spare driver, and an off-duty staff member — for helping passengers evacuate the Lewes train.
Heat-related rail disruption is not new. The 2003 European heatwave caused multiple UK derailments. The 2018 heatwave led to widespread speed restrictions and track buckles. In July 2022, the UK recorded 40 degrees Celsius for the first time. Rail services were heavily disrupted.
Network Rail’s Weather Resilience and Climate Change Adaptation Plan sets out long-term measures. Critics say funding and delivery have lagged. The current five-year control period, known as CP7, includes resilience funding. The Office of Rail and Road publishes annual safety statistics showing derailment trends.
Other countries design for higher temperatures. Spain’s AVE high-speed network operates at 45 degrees Celsius and above. France’s SNCF has heat protocols. Japan’s Shinkansen uses continuous thermal monitoring.
Freight services also face slow orders during heatwaves. This affects supply chains. Passenger compensation under Delay Repay covers delays but does not distinguish heat causes from mechanical faults.
The Victorian-era railway was not built for this climate. Adaptation plans exist. The question is whether investment matches the accelerating risk.
