PASSENGERS are being urged to only travel if "absolutely necessary" after a warning from the Met Office.
High temperatures have led to weather warnings today (25th June) and tomorrow.
While routes will remain open, travellers are being warned that reduced timetables will remain in place until the end of the working week.
Denise Wetton, Network Rail's Central route director, said:
"With weather warnings still in place for extremely hot weather, some services will now be reduced until the end of Friday.
"While all railway lines will remain open, running fewer trains will help us manage the impact of the hot weather and keep passengers and colleagues safe.
"We strongly advise customers to think carefully about their plans and only travel if it’s absolutely necessary in the areas most affected by the highest temperatures.
"If you do need to travel, please allow extra time, carry water to stay hydrated and be prepared for services to be busier than usual."
Network Rail said services were being disrupted due to the impact of extreme temperatures on tracks as well as power and signalling systems.
Details of service changes can be found at www.nationalrail.co.uk.
