Disruption on the roads and rail looks likely to ensue, as the mercury continues to rise.
Train tracks have buckled while some roads are in meltdown as the UK deals with its hottest spell of 2018.
Kirklees Council in West Yorkshire is preparing gritters to cope with melting roads and the M5 in Somerset was closed on Tuesday morning after tarmac failed to set in the hot weather.
Meanwhile train tracks in Glasgow buckled under the intense heat and passengers heading from New Malden, south-west London to Waterloo are facing speed restrictions until Friday to protect the vulnerable rails.
Elsewhere pavements in Edinburgh have buckled in the Scottish sunshine.
Network Rail has activated its ‘extreme weather action teams’ (EWATS) and installed ‘mini weather-stations’ and trackside probes to monitor local conditions.
It has introduced speed restrictions during the hottest part of the day at vulnerable locations and has painted parts of the rails white to absorb less heat.
Network Rail England and Wales managing director Andy Thomas said: “On very sunny days, rails in direct sunshine can be as much as 20C above air temperature causing the steel to expand markedly and could, if not carefully monitored and action taken, buckle causing travel disruption.
“Our engineers and specialist extreme weather teams are monitoring track-side temperatures and vulnerable locations and will, if necessary, introduce temporary speed restrictions during the hottest part of the day to keep trains running, albeit more slowly than normal.”
Rail Delivery Group chief executive Paul Plummer added: “This week could see some of the hottest weather of the year so we would advise people travelling by train to carry a water bottle and if they feel unwell, get off at the next stop where a member of staff will be happy to help.”
Trade unions have called on bosses to protect outdoor workers from sun and heat in the scorching weather.
The Trades Union Congress (TUC) urged employers to make sure staff on construction sites take breaks, drink water and wear sunscreen. It said bosses should organise work so tasks are done earlier in the morning or later in the afternoon when it has cooled down.
TUC General Secretary Frances O’Grady said: “We all love to see the sunshine. But working outdoors in sweltering conditions can be unbearable and dangerous.
“Bosses must ensure their staff are protected with regular breaks, lots of fluids, plenty of sunscreen and the right protective clothing.”
The water sector looks set to coast through the heatwave with minimum disruption after being hit hard by freezing weather in March.
A Water UK spokesperson said: “Britain is not about to go into a drought, despite the increase in temperatures. Water companies have plans in place to deal with dry spells and peaks in demand, and a wet Spring means water levels are healthy.
“We hope people enjoy the warm weather and continue to use water wisely.”
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