If you are travelling between Wimbledon and Waterloo today then you can expect delays.
National Rail have said that due to a speed restriction between the two stations, trains will be running at a reduced speed and some services may be delayed or revised.
In a statement put out by National Rail, it explained what South Western Railway was doing to solve the problem.
"Due a fault with the track, there is currently a speed restriction in place between Wimbledon and London Waterloo," it said.
"As a result, trains travelling towards London Waterloo are having to run at reduced speed through this area.
"Network Rail engineers are working hard to rectify the problem.
"However, some trains may incur minor delays or be revised at short notice throughout the day today."
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