Passengers heading to Gatwick Airport have been warned to allow extra time for travel after flooding on the tracks hit rail journeys.
Flooding in south London, caused by a burst water main near South Croydon station, saw services cancelled late on Monday.
Some rail services have resumed on Tuesday morning, including a reduced half-hourly Gatwick Express service.
Services are running on the hour and 30 minutes past the hour from London Victoria to Gatwick Airport, calling additionally at Clapham Junction and East Croydon, Gatwick Express said in a statement.
South Croydon and Purley Oaks stations will be closed all day Tuesday and there are timetable changes to many routes between London and the South Coast.
As well as the Gatwick Express, trains operated by Southern and First Capital Connect have also been hit by a reduced timetable.