South Western Railway commuters in Wimbledon are facing disruption the rest of this morning due to a signalling problem between Earlsfield and New Malden.
National Rail says a problem with the train detection system between the two stations means services running between Clapham Junction and Surbiton might be cancelled.
A spokesman said this is due to a track circuit failure, a system which detects the presence of trains on tracks.
He added: “When these fail, affected signals are held at red as the system cannot verify that the track beyond the signal is clear.
“As a result, all mainline trains towards Woking will need to use the ‘suburban line’ past the affected signal.”
Train services between London Waterloo to Hampton Court, Shepperton, as well as circular services via Richmond and Strawberry Hill are also affected.
They will not be able to stop at Raynes Park and New Malden.
National Rail predict the disruption will last until 12 noon today (August 16).
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