As the heatwave hits England and Wales with most areas expecting record temperatures, railway speed restrictions have been brought in amid fears the safety of the steel tracks could be affected.
Trains will mostly be limited to speeds of 90mph, down from 100mph or 125mph, while some could go as slow as 20mph! These changes have come after the Met Office issued a red extreme heat warning in England, with amber warnings in Scotland and Wales.
When steel gets very hot it expands and tracks can bend, flex and, in serious cases, buckle, Network Rail said. It has advised only essential travel and warned journeys would take significantly longer than usual with more chance of cancellations.
Those who do travel are advised to wear cool clothes, take handheld fans and ensure they have plenty of water, it said.
Many train companies will be running reduced timetables and passengers are being advised to check before they depart. The RAC motoring group has also warned some roads could melt as a result of the heat.
