Grant Shapps has warned it will take “decades” to make the UK’s transport system resilient to extreme heat.
The transport secretary said problems on rail and road will continue for years during heatwaves.
Brits are set to melt on the hottest UK day on record with temperatures predicted to hit 40C amid growing travel chaos.
Monday’s travel meltdown is expected to worsen on Tuesday as National Rail warns customers to only travel if “absolutely necessary”.
Shapps told Sky News: “This infrastructure is the things which take decades to build and replace.
“Three years ago, when I became transport secretary, quite literally one of the first conversations I had with the chief executive of Network Rail, Andrew Haines, was about these overhead lines on the railways which tend to sag in heat.
“He talked me through the new upgraded specifications which are going onto the railway lines, where they can withstand much higher levels of temperature and we’re going to see this a lot more regularly.
“We know that - we’ve seen the hottest days ever recorded have come in the last 10 to 15 years. So we’re going to see this more. It’s a huge infrastructure to replace.
“Decades, actually, to replace it all. Ditto with things like tarmac on the roads and obviously there are millions of miles of roads in total.
“There’s a long process of replacing it and upgrading it to withstand temperatures, either very hot or sometimes much colder than we’ve been used to, and these are the impacts of global warming.”
The cabinet minister also insisted Boris Johnson had not checked out early from No.10 after the prime minister was criticised for not taking more of an active role.
“It’s literally not true, in fact exactly the opposite is the truth,” Shapps stressed.
The prime minister did not attend last week’s Cobra meeting on the heatwave and is also skipped Monday’s meeting too.
He was also criticised for managing to find time to take a ride in an RAF Typhoon fighter jet last week.
Shown the prime minister’s ride in the RAF jet, Shapps tried to defend the flight.
“In the end he has responsibility for Britain’s security,” he said. “There is a war going on in Europe. Why on earth would he not go and meet with the RAF?”
Shapps said there was no Cobra meeting planned for Tuesday, with the prime minister instead chairing Cabinet.
Network Rail said: “There will be delays, cancellations and last-minute changes to train services due to the unprecedented record heat on those days.”
Merseyrail said the number of trains running and journey times will be “seriously affected”, with some routes closed completely.
LNER will run no trains from south of York and south of Leeds to London King’s Cross.
Southern, South Eastern, South Western Railway and Great Western Railway are among the dozens of train companies running significantly reduced services across the country.
Transport for London (TfL) said London’s rail network would also be running a reduced service on Tuesday due to safety restrictions put into place to deal with the heat.
Elsewhere, council gritters were on stand-by to spread light dustings of sand on melting roads.
The RAC anticipated that the number of vehicle breakdowns on Monday and Tuesday could be up to a fifth higher than normal.