Tens of thousands of commuters faced a nightmare journey to get home tonight as they endured major disruption after one of London's busiest train stations was shut.
Dozens of rush-hour services in and out of London Paddington were cancelled this afternoon - although there was nothing running until midday today - causing fury for the 98,000 people who use the station each day.
There were no TfL Rail services due to operate in rush hour - with limited Great Western Rail and Heathrow Express trains running, after a £16million Hitachi 'bullet' test train caused overhead wire damage in Ealing last night.
Services started to improve after noon as some lines were reopened, but GWR warned that 'delays are expected to last for at least the rest of the day' - and passengers were told to 'only travel if necessary'.
Some commuters claimed they had left the office early to avoid the rush-hour chaos, while others gave up this morning and decided to work from home instead. They described the delays as 'horrible' and a 'nightmare'.
Earlier, pictures posted online showed empty departure boards and barriers blocking all platforms at Paddington. Reading station was also in meltdown with huge crowds of people unable to board their trains.
Some people were left stranded on trains mid-journey – with a train from Paddington to Maidenhead being evacuated en route last night, with passengers wrapped in blankets staggering over the tracks.
It follows more chaos at London Victoria yesterday when a power failure wiped boards of travel information and caused widespread cancellations for commuters heading to South London, Sussex, Surrey and Kent.
Great Western Railway said the severe damage to overhead wires meant some trains were left stranded on the line between Paddington and Reading.
GWR trains into London were mainly only running as far as Reading this morning, with a reduced service from there to Slough. People travelling into London were told to use services into Waterloo, Marylebone or Euston.
Many trains became stranded between Paddington and Reading due to a loss of power supply. Network Rail said it expected to open two of the four train lines by midday, but warned disruption would last until the end of the day.
GWR added that a reduced timetable would impact most mainline routes to and from Paddington. Travellers trying to get to Heathrow were told to take the much slower Piccadilly Tube line to the airport, or bus replacements.
Delays on the Central, Circle, District, Hammersmith and City, Jubilee and Metropolitan London Underground lines compounded difficulties for commuters trying to get across the city after arriving at alternative rail hubs.
In an update at 12.45pm today, a GWR spokesman said: 'Some of the lines have reopened and a reduced train service is starting to operate into and out of London Paddington following last night's incident with a test train, however delays are expected to last for at least the rest of the day.
'Customers are advised to only travel if necessary and check before travelling. Tickets for GWR services today will also be valid for tomorrow, should customers choose to postpone their journey. Refunds will be given for those who choose not to travel.
'GWR tickets are still being accepted from London Waterloo, London Marylebone and London Euston for travel on South Western Railway, Chiltern Railways, Virgin Trains, West Midlands Railway and Transport for Wales. Heathrow Express is operating a limited service.'
An earlier statement said: 'There will be no trains between London Paddington and Reading until at least midday today as a result of overhead wire damage in the Ealing area last night.
'The train which caused the damage was an Hitachi test train operating between their London and Bristol depots, and not in passenger use. There will be no London commuter services and a reduced long-distance service timetable with trains starting from and terminating at Reading.
'We strongly advise customers to only travel if necessary in the Thames Valley and to check carefully before travelling elsewhere as long distance journeys are likely to be affected.
'Customers should travel from London Waterloo or London Marylebone instead, with tickets are being accepted on South Western Railway, Chiltern Railways, Virgin Trains, West Midlands Railway and Transport for Wales.'
GWR staff wheeled a trolley on to the Paddington concourse at around 8.30am to give away free tea, coffee and biscuits to frustrat