Two train derailments in southeast England amid an intense heatwave have prompted investigations into whether extreme temperatures contributed to the incidents, according to rail officials. On Thursday and Friday, separate derailments occurred near Lewes in East Sussex and Wickford in Essex, raising concerns about the impact of soaring heat on rail infrastructure.
The first derailment involved a Greater Anglia service traveling from London Victoria to Eastbourne, which left the tracks near Lewes on Thursday—the hottest day of the year, with temperatures exceeding 38 degrees Celsius. Of the 20 passengers taken to hospital, two sustained serious injuries. The following day, a Southend to London service derailed near Wickford, though no injuries were reported among the more than 60 passengers onboard. Both incidents required emergency response teams, including air ambulances and police.
Martin Frobisher, group safety and engineering director at Network Rail, confirmed that investigations are underway to determine the precise causes of both accidents. Speaking on a national radio program, he said the inquiry would consider a range of factors, including the influence of climate and weather conditions. “We don’t yet know the full facts and reasons for those derailments, but a very detailed investigation is under way and we’ll be getting to the bottom of it,” he said. Frobisher also indicated that adapting the rail network to cope with extreme temperatures may require additional funding and infrastructure upgrades.
His comments contrasted somewhat with earlier assurances from rail executives who emphasized the safety of the network during heatwaves. John Whitehurst, chief executive of Greater Thameslink Railway, described the railway as safe, citing routine inspections and the implementation of speed restrictions or service suspensions when necessary. However, experts have cautioned that hot weather can pose risks to rail integrity. William Powrie, professor of geotechnical engineering at the University of Southampton, explained that extreme heat causes continuously welded rails to expand. If the rails cannot expand freely, they may buckle, and dry ground conditions caused by drought can also destabilize track foundations. Powrie noted that while the heatwave could be a contributing factor in the East Sussex derailment, a thorough investigation is required to establish the exact chain of events.
The derailments occurred amid ongoing drought conditions and unprecedented high temperatures this summer. Thursday registered a peak temperature of 38.1 degrees Celsius in Surrey, marking the fifth heatwave of the year—a record number—with four consecutive days exceeding 36 degrees Celsius. Both incidents are being investigated by the Rail Accident Investigation Branch, with Network Rail conducting a parallel inquiry.
Frobisher underscored the challenges the rail network faces with changing climate patterns, pointing to the need for enhanced climate resilience measures. He noted that Network Rail currently allocates £1.6 billion toward adapting infrastructure for climate impacts but acknowledged that further investment will be essential to maintain safety and reliability under extreme weather conditions.