Transport for London has attributed widespread disruption on its railways to a ‘voltage dip’ caused by a fault on National Grid’s network.

It has apologised to passengers, but transport watchdog London TravelWatch has criticised TfL for not keeping the public updated more effectively.

Services on most lines are running normally again this morning, although an unrelated incident involving a passenger was causing disruption on Underground services through Barking early today.

Yesterday’s power cuts affected the Elizabeth Line as well as parts of the Underground and Overground networks.

Bakerloo services were suspended, along with those on parts of the Mildmay Line. The Circle, District, Jubilee, Northern, Piccadilly and Waterloo & City lines were also disrupted by delays and some partial closures, while many stations closed for a time. They included Covent Garden, Embankment, Oxford Circus, Paddington, Tottenham Court Road and Waterloo.

The Suffragette Line on the Overground was also closed because of an unrelated fire alert.

TfL’s chief operating officer Claire Mann said today: ‘All of the services that were interrupted due to a power supply issue to our network were returned to service yesterday. We're sorry for any disruption this caused to customers.’

National Grid also apologised, saying: ‘The fault was resolved within seconds and did not interrupt supply from our network, but a consequent voltage dip may have briefly affected power supplies on the low voltage distribution network in the area.’The fault is reported to have been caused by a fire at a sub-station.

Network Rail encountered problems of its own at London King’s Cross, where a downpour caused a power cut on several platforms in the main line station. Staff restored the power and cleaned up the rainwater, and all the affected platforms were reopened by about 18.00. No trains were cancelled.

London TravelWatch said: ‘We are glad to see that London’s transport network is back up and running after the disruption yesterday.

‘While incidents such as these are unpredictable, it was disappointing to see the lack of information and updates on TfL’s own social media feeds, particularly as other train operators were keeping passengers updated. Increased traffic to the TfL website also saw the site crashing and becoming unresponsive.

‘We accept that incidents like this can occur but do expect TfL to do much better when it comes to communicating with the millions of people who are reliant on their services. Directing all passengers to their website is not practical if the site then crashes, and people need to receive up-to-date information in order to continue their journeys with the least disruption.

‘Passengers also need reassurance that public transport services will be more resilient in future to incidents such as this.’

Railnews has invited TfL to comment.

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