A rail firm is warning of disruption to major train lines, cancellations at short notice and extended journey times as temperatures are set to soar over the coming days.

Avanti West Coast warned passengers who wish to use services between London Euston and Scotland to plan ahead due to the impact of the heat on rail lines.

The company tweeted on Thursday that services on Saturday July 16 and Sunday July 17 may be cancelled at short notice.

It also warned that services on Monday July 18 and Tuesday July 19 will be subject to amended timetables and extended journey times.

Steel rails absorb heat easily and tend to hover around 20 degrees above the surrounding air temperature, according to Network Rail.

With temperatures as high as 37C (98F) expected in London early next week, the hot weather – particularly direct sunlight – could cause track temperatures to reach up to 50C.

In such conditions, rails can bend, flex and, in some cases, buckle from the heat.

Trains, therefore, run at slower speeds in extremely hot weather to put less strain on the rails.

Network Rail’s west coast south route director James Dean said: “Keeping passengers moving is always our top priority. But we want people to be prepared.

“If the soaring temperatures do lead to us having to put in place slower speeds for safety reasons, please bear with us while our engineers work to fix the problem. It may mean some journeys take longer.

“For those who must travel by rail, we’d remind people to carry some water with them so they can stay hydrated and always check before travelling so they know exactly what to expect.”