Commuters face rush hour chaos on Thursday evening with severe delays being reported on four London Underground lines.
There are severe delays across the entire Piccadilly line due to a shortage of trains.
The Hammersmith and City and Circle lines were experiencing similar delays after a man was hit by a train at Shepherd’s Bush Market station earlier.
Emergency services rushed to the scene just before 1pm and the man was treated for serious injuries, but was later pronounced dead at the scene.
Meanwhile a signalling problem on the District line at Edgware Road caused severe delays between High Street Kensington and Edgware Road, with minor delays between High Street Kensington and Wimbledon and between Barking and Upminster.
Elsewhere there were minor delays on the Victoria line due to an earlier fault with the track at Victoria station.
Sources have told the BBC that there is a Piccadilly line train shortage due to drivers refusing to take out some trains over concerns with brakes.
Furious commuters have tweeted their concerns over the latest problems.
One said: "The incompetence of the @piccadiilyline is never ending. This morning they ran out of drivers and this evening they've ran out of trains!"
The incompetence of @piccadillyline is never ending. This morning they ran out of drivers and this evening they've ran out of trains! 👏🏼— Marshall ✈ (@marshall_mcf) March 16, 2017
Another said: "Shortage of trains? This line is a joke!"
Another Twitter user added: "Could you explain why there is a shortage of trains? Are they lost?"
@piccadillyline Could you explain why there is a shortage of trains? Are the lost?— Jon Myles (@jonmyles) March 16, 2017
One furious commuter said: "Why is there a shortage of trains again? Can't you get you house in order?
And another added: "How and why is there a shortage of trains? This happened in Dec 2016 for at least 3 weeks! Do I have to wait another 3 weeks."
@piccadillyline how and why is there a shortage of trains? This happened in Dec 2016 for at least 3 weeks! Do I have to wait another 3 weeks— Anjna Davda (@DavdaAnjna) March 16, 2017
An ongoing shortage of trains caused mayhem on the Piccadilly line in November and December last year.
Commuters faced severe disruption after trains with damaged wheels caused by wet weather were taken off the tracks to be repaired.
Brian Woodhead, Operations Director for the Piccadilly line, said: “I apologise to our customers for the disruption on the Piccadilly line today.
"This occurred after a number of drivers sought further assurance from us over the maintenance of trains on the line. We put our trains through a continual rigorous inspection and maintenance regime and we are completely confident in the safety of our trains.
"We are now working to get a good service on the line as soon as possible.”