A fire near a train track in the London Paddington area has caused major disruption, with services to Heathrow airport cancelled.
The fire caused an electricity supply failure which has left all lines between Paddington and the airport blocked, National Rail said.
Cancellations and delays to services are expected until ۷.۱۵pm, it added.
Photos on social media show large plumes of smoke rising from the Paddington area.
Great Western Railway (GWR) services to Reading have been cancelled, while the Elizabeth line is part-suspended.
No trains are running in either direction between Paddington and Heathrow, the Heathrow Express said.
The airport advised passengers to leave extra time for their journeys, adding that the Piccadilly line, which runs services to the airport, is also experiencing delays.
Transport for London (TfL) said the Elizabeth line is suspended between Paddington and Heathrow terminals four and five, and between Paddington and Reading, while the line to Abbey Wood is experiencing severe delays.
There are severe delays across the entire Piccadilly line due to an earlier trespasser at Hammersmith, according to the TfL website.
GWR said trains may be cancelled, delayed or terminated at and started back from Reading, with disruption expected until ۷pm.
The London fire brigade has been contacted for comment.
