Thousands of Londoners are facing a difficult commute on Wednesday morning as a signalling fault has affected the Elizabeth line and Heathrow Express.
National Rail has warned trains between London Paddington and Heathrow Terminal 5 may be delayed or cancelled.
On the London Overground, trains are unable to run between Gospel Oak and Camden Road on the Mildmay Line while Transport for London fix a faulty train.
Trains continue to be unable to run on a section of the Piccadilly Line after leaves formed a “very slippery” mulch on the rails that caused the 50-year-old trains to lose traction and skid.
Problems with worn-out wheels have caused a dire shortage of trains on the line, with only 60 of the 86 trains in the Piccadilly line fleet able to be used on Tuesday.
Delays and overcrowding caused by the part-closure of the Piccadilly line should start to ease by the “end of January”, Transport for London has promised.
Read the latest updates below.
Thameslink services hit by delays
07:02 , Jacob Phillips
A fault with the signalling system between London St Pancras International and West Hampstead is causing issues on Thameslink services.
Fewer trains are able to run on the line towards St Albans City. Services running to or from London St Pancras International and West Hampstead will be cancelled, delayed by up to 10 minutes or revised.
Disruption is expected until 11am.