
Commuters have been told to expect "major disruption" into Monday evening after a signalling problem at London Waterloo.
Fourteen platforms at the station were out of use after issues were first reported to National Rail at around 5.30am on Monday.
National Rail said all lines had reopened but services to and from Waterloo "may continue to be severely delayed or cancelled".
It advised rail users that "major disruption is expected" until 9pm.
South Western Railway (SWR) apologised to its passengers for the delays - and warned people to "avoid travelling if possible".
In an update on Monday afternoon, SWR said: "Following this morning's signalling problem at London Waterloo we are gradually reintroducing train services across our network.
"Customers are asked to avoid travelling if possible, as trains and crews are being returned to the correct positions to run train services.
"Later this afternoon, we expect to restore a reliable train service on our routes to Reading and Windsor & Eton Riverside, as well as our suburban routes.
"Significant disruption is expected on our long-distance routes to Exeter St Davids, Portsmouth and Weymouth until the end of the day."
National Rail said tickets will be accepted at no extra cost on a number of bus and train services.
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Any unused Monday-dated tickets will be valid for travel on Tuesday.
According to the Office of Rail and Road, London Waterloo was the fourth busiest train station in the UK last year, with an estimated 62.5 million entries and exits in 2023/24.
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