Alternative travel routes between Reading, London and Windsor have been advised after train line faults.
All lines between Paddington in west London and Reading are blocked because of damage to overhead electric wires, Network Rail said.
Services run by GWR, Heathrow Express and the Elizabeth line are disrupted, and GWR haved issued the following alternatives:
London to Windsor
London Waterloo to Windsor and Eton Riverside
West to Windsor
Shuttle service between Reading and Slough, calling at Maidenhead
West to London
Customers to London can change at Reading for SWR services to Waterloo
Engineers from Network rail are on site attempting to fix the problem.
A spokesperson for GWR said: "We are very sorry for the disruption today and are working with our colleagues at Network Rail to get services running again."
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