RAIL passengers are warned to check their routes as today's heatwave temperatures prompt speed restrictions on the lines.

Parts of the tracks as expected to exceed 50 degrees in parts of London and the Thames Valley sparking the limits between 1.30pm and 7pm.

Most services between London and Reading will be as timetabled but commuters should expect journeys to take around 10 to 15 minutes longer than usual.

Customers are also advised to check their routes, dirnk plenty of water and help staff keep an eye on any vulnerable passengers.

A GWR spokesperson said: "With temperatures in London set to exceed 30 degrees, the effect can bring the temperature of the rails to over 50 degrees, and we have been asked by Network Rail to drive more slowly as a result.

“We will continue to keep an eye on the situation, alongside Network Rail, and keep you updated throughout the day.”

A spokesperson for Network Rail explained: “Our modern rails are far more resistant to heat expansion and buckling than they used to be. However, a day this hot affects even our track, so we need to restrict speeds for safety. Full details are available on our website at networkrail.co.uk/delays explained.”

To be able to maintain the train timetable, the following services are expected to be cancelled:

· All Thames Valley branch lines to remain in branch operation but with no direct London services.

· London Paddington to Bedwyn and return services will operate between Bedwyn and Reading only

· London Paddington to Cheltenham Spa and return will operate between Swindon and Cheltenham Spa only

· London Paddington to Oxford direct (calling Slough, Reading, Didcot and Oxford) and return services are cancelled. Passengers are advised to travel to Didcot for connecting services to Oxford.