Rail passengers across south-east England faced severe disruption after a combination of incidents brought large parts of one of the UK’s busiest rail networks to a standstill.
A derailment at Selhurst depot in south London, alongside a critical signalling failure between London Blackfriars and Norwood Junction, led operators to issue an early-morning “do not travel” warning, an advisory rarely used except in the most serious situations.
The disruption affected services operated by Govia Thameslink Railway, including Thameslink, Southern and Gatwick Express routes.
What Caused the Network Breakdown
The most significant incident involved a train derailment inside Selhurst depot, a key operational site located near the point where several major routes converge. Although the derailment did not result in reported injuries, it blocked tracks leading toward central London, preventing trains from reaching their destinations.
At the same time, a fault in the signalling system between Blackfriars and Norwood Junction reduced the number of usable rail lines and forced trains that could still operate to run at reduced speeds.
This section of track is part of the Brighton Main Line, a Victorian-era route that carries an exceptionally high volume of services linking London with the south coast, Gatwick Airport, and multiple commuter corridors.
Because there are few viable alternatives when this line is compromised, delays and cancellations quickly cascaded across the wider network. Trains already en route became stranded, displacing drivers and onboard crews and compounding the operational challenges throughout the morning.
Widespread Impact on Passengers
As a result, multiple routes were suspended entirely, including services between Brighton and Cambridge, Bedford and Three Bridges, Orpington and Luton, and London Bridge and East Grinstead.
Other routes operated only partially, with some services terminating short of their usual destinations or being diverted via less direct paths. Even after the initial “do not travel” advice was lifted later in the morning, operators warned that major disruption would continue until the end of the day, with delays of up to an hour still likely.
Air travelers were also affected, as rail links to Gatwick Airport experienced knock-on delays, though the airport confirmed its station remained operational. To ease pressure on stranded passengers, ticket acceptance schemes were introduced across London buses, the Underground, the Elizabeth line, and several regional bus operators, allowing rail tickets to be used on alternative services at no extra cost.
Ongoing Disruption and Broader Questions
Rail officials emphasized that resolving both the derailment and the signalling fault required specialist teams and careful investigation, particularly given the safety implications.
While engineers worked to restore normal operations, the incident highlighted the fragility of heavily used rail corridors and the scale of disruption that can result when multiple failures occur simultaneously.
For passengers in Cambridgeshire, Sussex, Surrey and south London, the day served as a reminder of how interconnected the region’s rail services have become. When key junctions fail, disruption is rarely localized.
As services gradually recovered, transport authorities faced renewed scrutiny over infrastructure resilience, maintenance planning, and the challenge of keeping one of the UK’s most complex rail networks running smoothly under pressure.
