Overview
- An eight‑carriage Southern service (train 1F34) derailed north of Lewes on Thursday 13 August when its rear three vehicles overturned on the embankment while about 150 people were on board.
- RAIB’s initial on‑site work and CCTV from earlier trains show a visible track geometry irregularity on the approach to the derailment and on‑train recorder data indicate the train was travelling at about 65 mph when the driver applied the brakes.
- Thirty people were injured in the accident and 20 needed hospital treatment; two passengers who suffered serious injuries remain in hospital while the others have been discharged.
- Recovery of the damaged vehicles and repairs to the track are complex because of restricted access, proximity to a river and protected land, and the Lewes–Haywards Heath line remains closed with replacement buses and prolonged disruption expected.
- The RAIB will examine the track condition, embankment stability, recent hot dry weather and maintenance history and will publish a full report with safety recommendations at the end of its investigation.