Four people have been injured and almost 300 others evacuated after a train partially derailed near to Wimbledon.
Emergency services were called to the "low-speed partial derailment" on the South Western Railway line early on Monday.
Passengers were helped to safety by fire crews after a rear carriage came off the tracks near to Wimbledon station.
Commuters into London Waterloo faced "significant disruption", which National Rail warned would last most of the day.
Rail users on the District Line between Parsons Green and Wimbledon faced similar disruption.
London Fire Brigade said they were called to the derailment at 5.54am, with several fire crews attending.
It tweeted: "Specialist urban search and rescue crews have corrected the rear carriage that derailed nr #Wimbledon train station and are helping passengers from the train."
The fire service later reported that all passengers and crew had been safely evacuated.
A fire spokesperson said: "Our specialist Urban Search and Rescue teams quickly helped passengers from the train and thankfully there are only a few minor injuries."
Passengers were advised they could use tickets on Transport for London buses.