How Heatwaves Can Contribute to Train Derailments: Lessons from Bedford, Lewes and Wickford

As the UK experiences increasingly frequent and intense heatwaves, attention is turning to the impact that extreme temperatures can have on critical infrastructure, including the railway network. Recent incidents at Bedford, Lewes and Wickford have highlighted the challenges facing Britain’s railways as temperatures rise and climate change places increasing pressure on ageing infrastructure.

Why Does Hot Weather Affect Railways?

Railway tracks are primarily made from steel, which expands when heated. Network Rail explains that the rails in the UK have a stress-free temperature of 27 degrees, however ‘when the air temperature reaches 30 degrees, the temperature on the rail can actually be up to 20 degrees higher…such high temperatures are more than our track is designed to cope with. The problem is that when steel rails get hot, they expand, which can cause a buckled rail’.

In addition to rail expansion, prolonged hot and dry weather can affect embankments and ground conditions. Drying clay soils may shrink and move, potentially affecting the stability and alignment of railway lines. The tracks can be laid on solid concrete slabs to further resist contraction and expansion, but this is however, four times more expensive than a standard ballasted track.

The Lewes Derailment

The derailment near Lewes, East Sussex, on 13 August 2026 brought the issue of heat-related railway risks into focus. The Southern service travelling from London Victoria to Eastbourne derailed shortly before arriving at Lewes, causing three carriages to overturn. Around 30 people were injured, including two who suffered serious injuries. The incident occurred on one of the hottest days of the year, with temperatures exceeding 38°C in parts of southern England. Investigators from the Rail Accident Investigation Branch (RAIB) subsequently revealed that CCTV footage showed a track “geometry defect” at the location before the derailment occurred.

While the official investigation remains ongoing, the RAIB has confirmed that weather conditions, including the prolonged period of hot and dry weather leading up to the accident, form a key part of its inquiry due to the fact the site of the derailment is largely made up of clay soil, making it ‘sensitive to variations in water content and may undergo movement as moisture levels change’.

The Wickford Derailment

Just one day after the Lewes accident, a Greater Anglia service derailed near Wickford in Essex. Fortunately, unlike Lewes, the train remained upright and no passengers were seriously injured. Nevertheless, the incident caused major disruption and prompted another investigation.

The Wickford derailment occurred during the same intense heatwave affecting much of England. Although investigators have not yet established a definitive cause, Network Rail acknowledged in a statement that ‘the hot and dry conditions had presented significant challenges and they have taken several additional proactive steps to manage and mitigate the impact on the railway.’

The Bedford Incident

Although the Bedford rail accident of June 2026 was not deemed to be caused by a heatwave, it serves as a reminder of the devastating consequences that can follow rail safety failures. The collision near Bedford resulted in the death of a train driver and injuries to more than 160 people. Early investigations indicated that the accident involved signalling and train protection issues rather than weather-related track defects.

Preparing for a Hotter Future

Network Rail advised in their statement that the company has implemented several measures to reduce the risks associated with hot weather. These include closely monitoring the temperature of tracks, implementing speed restrictions where appropriate and planning track renewals around high temperatures.

Network Rail provided reassurance in their statement, advising the public that ‘Britain’s railways still rank among the safest in the world, and that safety is always our first consideration on the railway’.

Conclusion

The recent incidents at Bedford, Lewes and Wickford illustrate different aspects of railway safety, but together they highlight the growing challenges faced by transport infrastructure in a changing climate. As extreme weather events become more common, ensuring the resilience of the UK’s rail network will be essential. Continued investment in maintenance, monitoring and climate adaptation measures will play a vital role in keeping passengers safe and reducing the likelihood of future derailments.

Train accidents can give rise to complex questions surrounding liability, negligence and passenger rights. If you are interested in knowing more about the legal framework governing train accidents and the process of bringing a personal injury claim following a rail incident, please read our previous Nelsons blog on train accident claims.