A signalling system fault between Lewes and Eastbourne disrupted Southern rail services on the Sussex Coastway route, the operator has confirmed.

The failure affected one of the county's busiest coastal corridors. The Lewes–Eastbourne stretch of the East Coastway line carries a dense pattern of Southern services linking Brighton, Lewes, Eastbourne and Hastings, and any loss of signalling capability on the section removes the means by which trains are safely separated and routes are set through the affected area.

Southern issued an alert to passengers after the fault was identified, warning that services running between the two stations were subject to disruption while the problem was investigated. Signalling faults of this kind typically force control staff to impose speed restrictions, hold trains at stations or suspend traffic over the affected block sections until the equipment is examined and restored.

The disruption falls on a route with limited alternative capacity. The East Coastway line between Lewes and Eastbourne serves intermediate stations including Glynde, Berwick and Polegate, and passengers on these stretches have few practical options beyond replacement transport arranged by the operator or acceptance of extended journey times.

Southern advised passengers to check before travelling and to allow extra time for their journeys while the fault persisted. The operator's standard response to infrastructure failures of this nature includes holding tickets for later travel and, where disruption is prolonged, accepting tickets on alternative routes or operators' services where such paths exist.

Network Rail, which maintains and operates the signalling infrastructure on the route, is responsible for diagnosing and repairing faults of this kind. Signalling equipment on the Sussex coast includes legacy assets that have required repeated intervention in recent years, and failures in this category remain among the most common causes of delays on the region's network.

The signalling system on a conventional line divides the route into block sections and conveys movement authorities to drivers via lineside signals. When a fault disables the system or degrades it, trains cannot run at normal frequency through the affected area, and capacity on the whole corridor drops sharply because trains must be separated by greater margins or the section must be closed entirely.

Passengers completing journeys on the affected stretch were advised that some services could be cancelled, delayed by up to significant margins, or diverted, with replacement communications issued through the operator's live travel channels. Southern encouraged anyone travelling between Lewes and Eastbourne, and on the wider Brighton–Eastbourne–Hastings corridor, to monitor service updates as engineers worked on the fault.

No timeframe for full restoration was given in the initial alert, and the operator indicated that service recovery would depend on the nature of the fault identified by responding staff. Passengers whose journeys were disrupted by the failure may be entitled to compensation under the Delay Repay scheme, which Southern operates across its network for delays above the qualifying threshold.

The incident is the latest in a series of infrastructure-driven disruptions on Sussex routes, where ageing signalling assets remain a factor in service reliability. Further updates were expected from Southern and Network Rail as diagnosis of the fault progressed and normal working between Lewes and Eastbourne was restored.