Derailed Train at London Depot Sparks Travel Chaos Across Three Major Rail Networks

A train derailment at a south London depot combined with signalling failures brought three major rail operators to a standstill on Wednesday, forcing officials to tell passengers to stay home during the morning rush hour.
The dual crisis hit Govia Thameslink Railway – Britain’s largest rail franchise – causing unprecedented disruption across Southern, Thameslink and Gatwick Express services throughout the day.
An empty passenger train came off the tracks near Selhurst depot in south-east London, blocking other services from leaving the facility. Network Rail released images showing the train remained upright following the incident, with officials confirming no injuries were reported. However, the derailment effectively trapped multiple trains inside the depot, unable to begin their scheduled services.
Compounding the crisis, a separate signalling system malfunction occurred between London Blackfriars and Norwood Junction. The technical fault reduced the number of operational rail lines and forced remaining services to crawl at significantly reduced speeds.
The combination of problems proved catastrophic for the network. GTR issued an urgent warning at 7.52am telling customers to avoid travelling “if at all possible” – one of the most severe advisories a rail operator can issue. While this alert was withdrawn by 10am, transport bosses cautioned that knock-on effects would plague services throughout the entire day.
The disruption completely shut down several key commuter routes. Services between London Bridge and East Grinstead ground to a halt, as did trains running between Brighton and Cambridge, and the Bedford to Three Bridges corridor. Numerous additional Thameslink routes also suffered severe interruption.
Passengers who did attempt to travel faced delays stretching up to a full hour, with many services cancelled outright or running with revised timetables. The signalling problems meant trains using the limited available tracks had to proceed at cautious speeds, creating a ripple effect of delays across the entire network.
In a joint statement, Govia Thameslink Railway and Network Rail acknowledged the severe impact on customers’ journeys and apologised for the disruption. The organisations said engineering teams were racing to resolve both the depot derailment and the signalling malfunction as quickly as possible.
Network operators confirmed they would accept tickets on alternative routes where available, offering some flexibility to stranded passengers trying to reach their destinations.
The incident highlights the fragility of the rail network, where simultaneous technical failures can bring vast swathes of services to a standstill, affecting tens of thousands of commuters across south-east England.​​​​​​​​​​​​​​​​