Four fire engines and around 25 firefighters were called to a fire on Black Prince Road in Lambeth.
Firefighters tackled a fire on a railway arch, which was causing heavy smoke to billow onto the railway track and damaged half or the arch.
The Brigade was called at 0904 and the fire was under control by 1022. Fire crews from Lambeth and Soho fire stations attended the scene.
The cause of the fire will be investigated.