All lines are closed between Havant and Portsmouth Harbour after a person was hit by a train this evening (Saturday).
Southern Rail said train services running to and from these stations will be cancelled or delayed until the end of the day.
It added: "Due to a person being hit by a train between Havant and Portsmouth Harbour all lines are closed.
"Replacement buses are running between Petersfield and Portsmouth Harbour. Ticket acceptance is currently in place with stagecoach 700.
"For further information or onward travel advice please speak to a member of staff or use a station help point."
Emergency services are on the scene.