Southern train derails near Lewes leaving about 20 injured

A Southern train operated by Greater Thameslink Railway derailed on the East Coastway line between Cooksbridge and Lewes in East Sussex at about 15:54 BST on 13 August 2026, just north of the Lewes tunnel.

The service was the 14:24 from London Victoria to Eastbourne. Three rear carriages of the eight-coach Electrostar left the rails and overturned on their side, with part of the formation sliding partly down the embankment. Around 150 passengers were on board.

According to British Transport Police and South East Coast Ambulance Service, two people suffered serious injuries and about 20 people were hurt in total. Earlier reports had put the lighter injuries at between nine and 18. No one was killed. All passengers were evacuated safely, though some were initially trapped in the carriages. Casualties were treated at the scene, some were taken to hospital, and those not needing admission were directed to a local community centre.

Emergency services declared a major incident. British Transport Police and Sussex Police attended, along with East Sussex Fire and Rescue Service with 10 appliances, a command unit and technical teams, and South East Coast Ambulance Service with more than 20 ambulances and three air ambulances.

Passengers described violent swaying, a sudden jolt or “jump” of a carriage, emergency braking, smoke and dust. One passenger travelling with her daughter spoke of pandemonium and screaming. Others said they first thought the train had struck something or someone.

The Rail Accident Investigation Branch sent inspectors to the site at once. The official cause remains unknown. Online and media discussion has pointed to heat-related track buckling after temperatures in south-east England rose above 37°C that day, one of the hottest of 2026, and aerial images showed clearly distorted rails. On 12 August Southern had reported a track safety check on the Lewes to Haywards Heath section, and some local residents and rail commentators described the location as a known problem stretch. Railway engineers have cautioned that track damage can be either a cause or a consequence of a derailment. Network Rail declined to speculate while the RAIB inquiry continues.

All lines through Lewes were closed, including Haywards Heath–Lewes, Brighton–Lewes and Eastbourne/Seaford–Lewes. Southern advised passengers not to travel in the area, allowed tickets on alternative Southern, Thameslink and Gatwick Express routes and replacement buses, and recommended allowing an extra 150 minutes for journeys towards Gatwick.

As of the morning of 14 August the RAIB investigation was still under way, services remained partly restricted, and no official cause had been confirmed.