A person has been hit by a train at Wivelsfield tonight (September 24).
Police and ambulance crews attended.
First Capital Connect and Southern Railway report disruption to services on the Brighton to London line.
Bus services and alternative routes are being provided for passengers as no trains can pass through Wivesfield in either direction.
Souther reports delays between East Croydon and Brighton, Hove and Lewes until at least 8.45pm.
www.nationalrail.co.uk said: “Trains are currently unable to run between Brighton and Haywards Heath. Replacement buses are now operating between Brighton, Haywards Heath, Lewes and Hove. Alternative routes where tickets will be accepted. Thameslink and Southern have mutual ticket acceptance. Southern passengers may use South West Trains, Southeastern, London Overground and London Underground via any reasonable route. Southern passengers may also use First Great Western services between Redhill and Guildford.”