A “do not travel” alert has been issued by the UK’s largest railway franchise.
Train operators Southern, Thameslink and Gatwick Express – all part of the Govia Thameslink Railway (GTR) franchise in south-east England – urged passengers not to travel on Wednesday morning “if at all possible” because of “multiple incidents”.
A train derailed near a depot in Selhurst, south-east London, and there was a fault with the signalling system between London Blackfriars and Norwood Junction.
⚠️We’re responding to a suspected derailment involving a train near Selhurst Depot, which is blocking the lines towards Norwood Junction and London Bridge
— Network Rail Kent & Sussex (@NetworkRailSE) February 4, 2026
❌This is causing disruption to services in the area
👷There are no confirmed injuries at this time. Our teams are on site… pic.twitter.com/GIU0h0XF4j
The train operators told passengers: “A number of incidents across the Gatwick Express, Southern and Thameslink networks mean that all lines are disrupted.
“Trains across these networks may be cancelled, severely delayed by up to 60 minutes or revised.”
Disruption is expected to continue for the rest of the day.
Network Rail released an image of the derailed Southern train showing it remained upright.
It added there were “no confirmed injuries”.
The incident is preventing other trains from leaving the depot.
National Rail Enquiries said the signalling fault means fewer rail lines are available for use between Norwood Junction and London Blackfriars, and trains running on the available lines must travel at slower speeds than normal.
That means services are suspended on routes between: London Bridge and East Grinstead; Orpington and Luton; Brighton and Cambridge; and Bedford and Three Bridges.
⚠️NEW: #Selhurst Disruption to London Overground services between Sydenham and West Croydon expected until 07:30https://t.co/i3qSKS6itV
— National Rail (@nationalrailenq) February 4, 2026
Trains that usually run between Welwyn Garden City and Sevenoaks are only operating between London Blackfriars and Sevenoaks.
Services between Rainham and Luton are only running between Rainham and Dartford.
Trains that normally operate between Horsham and Peterborough, or Brighton and Bedford, may run via Selhurst instead of Norwood Junction.
A GTR spokesperson said: “We’re very sorry for the disruption that customers have experienced this morning.
“A fault with the signalling system between Norwood Junction and London Bridge, along with a train derailment at Selhurst depot, are causing the disruption.
“We’re working with Network Rail to resolve these issues as quickly as possible.
“We advise customers to check our website and social media accounts for the latest travel information.”
Passengers whose journeys are disrupted are able to use tickets on certain alternative routes.
GTR, which also includes operator Great Northern, is the UK’s largest railway franchise in terms of the number of passengers carried.
Some 18% of train journeys in the UK are made on GTR services, according to the company.
