Part of the Elizabeth line is suspended while the rest of the line is severely delayed.
As of 3.30pm on Monday, there was no service between Paddington and Reading/Heathrow Terminals.
This is because of a trespasser on the track at in the Ealing Broadway area.
It comes as motorists are facing serious delays on key routes around London after the M3 was shut following a crash involving a road sweeper and a serious collision closed a huge section of the M2.
Around eight miles of the motorway in Surrey were closed for over an hour due to the overturned vehicle, which also caused a large diesel spillage.
The road was shut southbound from Junction 2 (M25 interchange) to J3 A322 (Lightwater) at around 12.20pm, bringing all traffic to a standstill.
Trapped traffic is being allowed to pass through one lane by the scene and three lanes remain closed.Meanwhile a “serious collision” closed a huge section of the M2 in Kent into London but this has since cleared up.
