Passengers on some of the busiest rail routes in the country suffered travel disruption on Friday because of multiple track circuit failures.
South Western Railway issued a message to customers at lunchtime recommending not to travel on its services at present, saying tickets will be valid on Saturday.
The company said: “We have been informed that there are multiple track circuit failures in the Surbiton area, affecting all trains heading away from London Waterloo. Trains are having to be talked past signals and run under caution.
“Trains may be subject to short notice changes. Passengers are requested to please use other London terminals.”
Changes were made on many lines and London Waterloo to Hampton Court services were suspended in both directions.
Replacement road transport was requested to run between Hampton Court and Wimbledon, but was not running to a fixed timetable.
Network Rail Southern region managing director John Halsall said: “I’m so sorry for the major problems passengers are facing today and both Network Rail and South Western Railway are asking people not to travel on trains from Waterloo.
“This is an unusually complex problem and we’re working as hard as we can to resolve it, but even if we can fix it soon, the disruption is likely to continue for the rest of the day.
“We can only run a very limited service from London Waterloo, and as a result we are having to limit the number of trains we’re running the other way, otherwise we will soon run out of trains at one end and space to put them at the other.
“As soon as we can get things moving normally again we will, but until then please don’t travel.”
SWR’s managing director Claire Mann said: “We are so sorry that, due to track circuit failures at Surbiton, our customers are having to deal with disrupted journeys today.
“Unfortunately, this disruption is so severe that we are urging our customers not to travel on our network until further notice.
“Whilst we work with Network Rail to fix this problem, a rail replacement bus service is currently in operation on affected routes, and SWR tickets are being accepted on certain TfL, Southern Railway, GWR and Cross Country services along with some local bus routes.”