Disruption to trains serving the UK’s second busiest station is expected to continue until late on Friday morning.
The tens of thousands of people who use London Victoria each day are being warned that some Southern, Gatwick Express and Thameslink services could be axed, delayed by up to half an hour or changed.
All lines have reopened between East Croydon in south London and Victoria after a signalling fault caused havoc on the major commuter route throughout Thursday.
The knock-on effect means services running to and from London Victoria on Friday morning may be cancelled or formed of fewer carriages than usual.
Rail users have been advised to travel as planned on Friday morning and a “good” service is expected to have resumed by 10am.
“All lines have reopened between East Croydon and London Victoria, following a fault with the signalling system at Streatham Common. However, trains may continue to be cancelled, delayed by up to 30 minutes or revised,” National Rail said.
“We anticipate a good service will be operating by 10:00.”
Rail bosses had initially warned disruption would continue until at least 7am on Friday.
The problem with signalling equipment at Streatham Common in south London was discovered at 10.30pm on Wednesday.
The cause of the fault was traced to the failure of the power supply linked to signalling equipment.
Around 210,000 passengers use London Victoria each day.