Warnings that the country’s infrastructure would not be able to cope with extreme weather conditions have become reality – with roads melting, airport runways damaged and rails bending in the heat.
Transport Secretary Grant Shapps admitted the UK’s transport network could not cope with the record heat, saying Victorian-era infrastructure was “simply not built to withstand this type of temperature”.
But why are extreme temperatures wreaking such havoc on the UK’s transport network?
Road damage was reported across the country due to the heat, while Luton Airport was forced to close its runway on Monday after a defect in the tarmac was discovered.
On Tuesday, the A14 in Cambridgeshire – a major transport artery to Britain’s largest container port – was the latest road to give way.
Police tweeted an image of a sunken road, saying: “No, the A14 is not turning into a skatepark… unfortunately the road surface doesn’t do well in this heat.”
How come our roads are melting?
British roads are made of asphalt, but some are made of concrete.
The Road Surface Treatment Association said the surface can start to melt when it reaches 50C.
This can happen even when the air temperature drops to 20C at the end of the day, as the road surface absorbs heat during the heat of the day.
Why can’t railways cope with extreme heat?
Forecasters said temperatures on road surfaces could reach 60C or higher due to their prolonged exposure to the sun.
That was certainly true of the rail network on Monday, with Network Rail revealing the hottest track reached 62C (144F) in Suffolk.
Network Rail says British rails are pre-stressed to help them withstand high temperatures.
British rails have a stress-free temperature of 27 degrees – the UK’s average summer rail temperature. Countries with traditionally hotter climates will “tune” the rails to higher temperatures.
When the air temperature reaches 30 degrees, the rail temperature can actually be up to 20 degrees higher.
When steel rails get hot, they expand, which can cause the rail to buckle – and increase the risk of a derailment.
Why can’t we make adjustments to cope?
Network Rail said some countries regularly experience extreme temperatures that affect their railways and may adjust their tracks between summer and winter or have other measures to manage the effects in the long term.
But it said it would not be “practical or cost-effective” to adjust the rails to manage the effects of temperature in the long term.
What causes distortion?
Metal can expand or contract depending on temperature. This generates forces that try to push and pull the rail out of shape.
Railway engineers try to prevent this by using sleepers and ballast.
Network Rail says measures used in other countries include the use of a solid concrete slab to contain the higher forces – but warns that “slab rails cost approximately four times more to install than standard ballasted tracks”.
It says: “The movement of trains also generates forces in the track. The higher the speed, the greater the power of the train.
“When thermal expansion forces are high, trains deliberately slow down to reduce the additional forces they apply to the rail.”
When will UK infrastructure improve to cope?
Mr Shapps said rail and road problems would continue for decades during extreme heat.
Asked how long it would take to upgrade the existing rail infrastructure to make it more sustainable, he told Sky News: “Decades actually to replace everything. Same with asphalt on roads.”
He told BBC Breakfast: “We’ve seen significant travel disruption, we’re likely to see the UK’s hottest day on record today and the infrastructure, much of it built in Victorian times, just wasn’t built to withstand that type of temperature – and it will be many years before we can replace the infrastructure with one that can, because the temperatures are so extreme.”
Asked if the transit system could handle the weather, he said: “The simple answer right now is no.”
Workers repair the runway at Luton Airport Picture: ITV News
Luton Airport had to divert flights on Monday after high temperatures melted the surface of its runway.
The airport said it had discovered a surface defect that was being repaired and apologized to passengers.
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