There are major delays on the District Line due to an earlier trespassing incident on the track at Parsons Green, Transport for London has said.
The incident has caused delays to services between Wimbledon to Edgware Road.
There is a good service on the rest of the line.
Meanwhile, there are also minor delays on the Northern Line due to a shortage of trains.
Earlier a power supply failure in south London disrupted trains on the London Overground and Southern network on Tuesday afternoon.
The issue, between Norwood Junction and West Croydon, left some lines blocked, says National Rail.
London Overground trains between Highbury and Islington and West Croydon were affected, as were Southern services between London Bridge and Epsom, and also between London Victoria and Epsom Downs.
