UK railway warns train tracks around London could buckle because of the extreme heat

• Temperatures in the UK on Tuesday shattered records, reaching a high of 104.36 degrees Fahrenheit.
• The extreme heat can cause railway tracks to buckle in the scorching temperatures.

Train riders in the UK have been warned not to travel into the "red zone" around London amid a record-breaking heatwave that can cause railway tracks to buckle in the scorching temperatures.

Britain's Network Rail advised travelers to stay home instead of riding the railways as temperatures in the UK on Tuesday shattered records, reaching a high of 104.36 degrees Fahrenheit (40.2 degrees Celsius) for the first time ever.

"Temperatures are still climbing in many places," the UK's Met Office warned in a tweet.

Network Rail tweeted that the company and train operators "have upgraded travel advice for services heading north out of London into the weather warning 'red zone' to DO NOT TRAVEL."

"With free refunds/ticket swaps available, the advice is to stay home and replan your journey," the company said.

The company said on Monday that services "were heavily impacted by the extreme heat today with buckled rails reported and overhead wire systems failing."

The railway company's hottest track recorded on Monday was 62 degrees Celsius, or 143.6 degrees Fahrenheit, in the county of Suffolk.

"Rail temperature can be about 20°C higher than air temperature, causing it to expand, bend and break," Network Rail said.

Additionally, speed restrictions for trains across the area have been put in place to help prevent the steel tracks from buckling.

The UK issued its first "red extreme heat" warning zone around London this week.

The "red extreme heat" weather warning was issued for Monday and Tuesday for parts of central, northern, eastern, and southeastern England.