Increased flooding because of rising sea levels could see Network Rail spending almost ten times more on sea defences by 2040 in some parts of the UK.
The findings, from research published in the Journal of Transport Geography, focus on the impact of sea level rises on the Dawlish to Teignmouth stretch of the main London to Penzance route in in the South West of England. The route was closed for two months in early 2014 after it was wrecked by coastal storms.
While Network Rail currently spends around £800,000 a year maintaining sea defences between Dawlish and Teignmouth, the research finds this could rise to between £5.8 million and £7.6 million a year by 2040.
Rising sea levels, coupled with coastal storms and floods, pose major challenges for rail operators and governments. The study forecasts that rail services to and from the South West of England could be disrupted for more than 10% of each year by 2040 and almost a third by 2100.
Jon Shaw, professor of transport geography at Plymouth University, said: "Billions of pounds have been committed to the HS2 rail link, but our predictions suggest that just eight years after its completion, rail users in the South West will be facing a situation where their only service cannot function for 40 days each year.”
Researchers from Plymouth University, the University of Leeds and the University of York analysed 150 years of historical data against the sea level rises predicted by the United Kingdom Climate Impact Programme (UKCIP) and identified a link between sea-level change and rail incidents.
The results of the analysis show that current disruption of 9.6 days per year on the railway line to the South West could rise by more than 300% by 2040, 40 days per year, and up to 1170%, 120 days per year, by 2100.
The researchers said there could be similar implications for other vulnerable stretches of railway lines throughout Wales, South East England, the Cumbria coast and Scotland, as well as internationally in the United States, Australia, India and Thailand.
Dr David Dawson, lead author on the study from the University Of Leeds, said: “Our rail history clearly shows the problem is worsening. Defence improvements may be able to improve the situation in the short to medium term but the long-term future of the line is what is really worrying.
“Coastal transport routes around the globe face similar problems from rising sea levels and we need to think carefully how we adapt to these problems so as not to create further issues for future generations. Studies such as this provide important evidence to start strategic planning.”