A fire on the tracks at Vauxhall station in London is causing major disruption in and out of the city.
It broke out in signalling cables underneath one of the platforms at about 02:35 BST.
The power has been switched off and as a result services to and from Waterloo are severely delayed.
Services on the Hounslow loop and via Richmond and Kingston are not running and the bus station at Vauxhall has also been closed.
London Fire Brigade station manager John Ryan said: “Once the power was isolated firefighters quickly got to work to tackle the fire.
“We’re currently assessing how much electrical cabling has been affected and damping down pockets of fire.”
South West Trains said it had limited services and asked travellers to use alternative routes into London.
Tickets will be accepted on Southern, Great Western Railway and Transport for London services.
A South West Trains spokesman said: “There are significantly fewer trains running than normal. We are very sorry for the inconvenience caused to passengers this morning.”
An investigation into the cause of the fire is under way.