UK Railways Face Challenges from Rising Summer Temperatures
As UK summers grow hotter, the country's railway infrastructure faces significant challenges, including the risk of rail buckling and equipment failures. Steel rails, designed to operate up to around 46°C, can reach surface temperatures of approximately 51°C, causing dangerous lateral buckling known as 'sun-kinks'. This distortion poses a derailment risk, necessitating speed reductions for safety, according to Network Rail.
Rails in the UK are laid at a 'stress-free temperature' of about 27°C. When temperatures exceed this, the rails are under stress, leading to potential buckling. Other countries, like the US, use higher stress-free temperatures to reduce summer expansion risks, albeit with increased brittleness in winter.
Network Rail has implemented several mitigation strategies, including remote temperature monitoring and local speed restrictions when critical rail temperatures are approached. Additionally, painting rails white can reduce heat absorption, lowering temperatures by 5–10°C. Structural solutions, such as continuous welded rail and slab track, are also employed to minimize expansion risks.
Signalling equipment is similarly vulnerable, with legacy systems housed in metal cabinets prone to overheating. South Eastern Railway and Network Rail are trialing passive cooling technologies, such as IsoMat panels, which have reduced internal cabinet temperatures by over 21% without requiring power or maintenance.
The UK government, acknowledging these risks, has committed £2.6 billion to weather-resilience improvements from April 2024 to March 2029. Network Rail has developed regional Weather Resilience and Climate Change Adaptation plans to address these challenges.