A signalling fault has disrupted Southern Rail services in East Sussex, forcing the operator to adjust timetables while engineers work on the affected equipment.

Southern, the Govia Thameslink Railway franchise that operates regional and commuter services across Sussex, Surrey and parts of Kent, reported the fault affecting signalling infrastructure in East Sussex. Signalling failures of this type prevent control staff from clearing routes electronically in the normal way, which typically triggers delays, cancellations and short-notice timetable revisions until the fault is located and repaired.

The disruption centred on routes in East Sussex, the county served by Southern's network of lines connecting coastal towns such as Eastbourne and Hastings with London terminals and with interchange hubs including Brighton and Lewes. Passengers travelling through the affected area were advised to check journey details before departure, as service patterns could change while the fault persisted.

Network Rail, which maintains the signalling infrastructure on the routes Southern operates, is responsible for the repair work. Signalling assets in the region range from legacy colour-light installations to equipment controlled from area operating centres, and faults in track-circuit or interlocking systems can require specialist response before full capacity is restored.

The incident follows a familiar pattern for passengers on the Sussex routes, where ageing signalling assets have repeatedly caused disruption in recent years. Each failure of this kind constrains the number of trains control staff can safely route through the affected area, reducing line capacity and lengthening journey times even where services continue to run.

Southern has not yet indicated how long repairs will take or when a full timetable will resume. Passengers should expect continued variation in service levels until Network Rail confirms the fault has been fixed and normal signalling operation resumes across the affected East Sussex routes.