Travel chaos hit train services in London during rush-hour when a fire broke out in Deptford.
Thousands of commuters faced huge delays on trains on the east London Overground line.
A warehouse fire sent thick black pouring into the air and across train tracks near New Cross station, causing knock-on disruption.
Lines were suspended between Highbury and Islington and New Cross, West Croydon, Crystal Palace and Clapham.
Transport staff reportedly ushered passengers out of stations in a bid to prevent overcrowding on platforms.
Eight fire engines were tackling the blaze at its height around 75m from New Cross station. It was brought under control by around 6.30am, but severe delays continued for up to two hours.
"An exclusion zone was placed in the area while the London Fire Brigade worked to put out the fire which is now extinguished; the fire meant that no trains were able be run in or out of the depot," said Mike Stubbs, director of London Overground.
Fire brigade spokesman Keith Fearn said: "When crews arrived, they were faced with thick black smoke pouring from the building and drifting for about 75m."
The cause of the fire was under investigation.