The rail network is still feeling the brunt of Storm Bert, with some lines affected by speed restrictions and flooding.
Trains between Gatwick Airport and London Victoria face cancellations and delays of up to 10 minutes after a defective track was discovered between Gatwick and Purley.
National Rail said the disruption is set to last until 1pm.
Gatwick Express services are suspended, while Thameslink services between Three Bridges and Bedford are reduced.
Southern trains between London and Gatwick Airport are also affected.