Thames Valley trains disrupted by hot weather

A buckled track caused by extreme heat in 2006

Hot weather is set to disrupt trains in the Thames Valley area with speeds being cut over fears of rails buckling.

First Great Western has amended some services from midday to 20:00 BST because of the heat.

There will be no fast trains between London Paddington and Bourne End in Buckinghamshire or Henley-on-Thames in Oxfordshire.

Network Rail said if the track buckled the line must be closed for repairs, "causing considerable disruption".

Trains from London Paddington will finish at Twyford for a connection with a branch line service to Henley-on-Thames.

Passengers travelling to Bourne End will see their services from Paddington terminate at Maidenhead and will also have to complete their journey on a branch line train.

Temperatures are set to hit 30C (86F) in parts of the Thames Valley, the Met Office said.

Network Rail said the set of points needed for the affected services were susceptible to hot weather and had therefore been designated as "high risk".

A spokesman said: "If the points failed it would completely block the line into one of London's busiest stations.

"The last thing we want is people sat stuck on trains in hot weather."

To prevent buckling, small gaps are left between sections of steel rails to allow them to expand and contract as temperatures change normally throughout the year.

However, in extreme hot spells when the air temperature reaches 30C (86F) the rails can reach 50C (122F) meaning they are at risk of buckling, resulting in speed restrictions.

Tracks abroad are often set up for the constant higher temperatures.