Trains between London and Clapham Junction have been cancelled because of a large fire next to the railway track.
Sixty firefighters are tackling the blaze in a warehouse next to Clapham Junction station.
Trains between the station and London Victoria and Waterloo have been cancelled after the fire service advised operators to close the line.
A spokesman for Southern Railway said disruptions could continue into tomorrow morning and advised passengers to check the situation before they travel.
Southern Rail tweeted: "Due to a large lineside fire in the Battersea Park area, the London Fire Brigade have asked Network Rail to close all lines between Clapham Junction and London Victoria.
"We are unable to run any services into or out of London Victoria at present. Passengers are advised to travel to London Bridge or Blackfriars and change where necessary. Tickets will be valid on Thameslink Southeastern South West Trains, London Underground or London Bus."
Sixty firefighters were tackling the blaze late on Wednesday night at the industrial estate in Culvert Place, Battersea, south London.
Flames soared above rooftops next to the railway line, while smoke could be seen from miles around.
London Fire Brigade it received a call at 8.51pm on Wednesday and sent crews from Lambeth, Brixton, Tooting, Chelsea and Peckham to the scene.
They said: "Eight fire engines and around 60 firefighters and officers have been called to a large fire on an industrial estate on Culvert Place in Battersea.
"The fire is affecting an industrial unit and smoke from the blaze can be seen for miles around. Brigade 999 control officers have taken around 90 emergency calls to the incident."
The cause of the fire remains unknown.