A person has been hit by a train between Havant and Guildford.
South Western Railway said that trains between London and Portsmouth were delayed because of the incident earlier this afternoon.
Trains to and from London Waterloo are currently delayed by up to 30 minutes, with disruption expected until the end of service.
It also follows an earlier signal problem at Clapham Junction which led to temporary speed restrictions, and a points failure at Basingstoke.
For the latest updates go to the National Rail website.