Around half of services to London out of Brighton have been cancelled because of major flooding at Patcham, near Preston Park.
Tim Shoveller, Managing Director of SWT has written to all passengers to explain what the rail operator is doing to keep services running.
Like most rail companies across the ITV News Meridian region, Cross Country trains are also affected by the severe weather conditions.
Services through #Bagshot have delays due to earlier trespassers on the line earlier.
A major signalling problem in the Wimbledon area blocked both of the lines away from London Waterloo - all lines now open again. South West Trains are making changes to services to try and mitigate delays._ _
- London Waterloo to Dorking services will not run in either direction from 13:24 until further notice.
- London Waterloo to Hampton Court will not run in either direction from 13:06 until further notice.
- London Waterloo to Guildford via Cobham services will call additionally at Berrylands in both directions.
- Train services between London Waterloo and Salisbury/Exeter/Bristol will not run between Basingstoke and London Waterloo. Customers will need to change trains at Basingstoke to complete their journey.
Evacuation of Waterloo station http://t.co/2bVZrNuLRP
#Waterloo - Customers are able to come into the station again. Trains are now running into and out of Waterloo with delay!
#Waterloo - Please listen to our teams on the ground while we investigate the cause of the alarm. Trains are being held outside Waterloo.
We were called to investigate a fire alarm at #Waterloo station but to reassure you there is no fire. We will be leaving the scene shortly.
Waterloo Station has been evacuated due to fire alert but just reopened http://t.co/x4qso5niDa