Police were called to reports of a person on the tracks by Hampden Park level crossing this afternoon (Monday).
According to British Transport Police, officers were sent to the tracks near the railway station to make inquiries at around 12.50pm.
The spokesperson said officers are currently trying to track the man involved, who is no longer on the tracks.
Southern Rail says services have been disrupted, with none running between Polegate and Eastbourne, but tickets are now being accepted on Brighton and Hove buses.
Sussex Police officers were also called to the scene. A spokesperson said, “Police attended reports of an incident on the train tracks at the Mountfield Road, Eastbourne, level crossing at 12.50pm on Monday (October 16).”