A “near-normal” service is expected at London Paddington railway station on Thursday after damage to overhead electric wires caused severe disruption at the busy transport hub.

The station, which serves around 100,000 passengers each day, was deserted for much of Wednesday after services on many key routes were suspended.

Trains were unable to run between the capital and Slough or Heathrow Airport after 500 metres of overhead power cables suffered extensive damage by the testing of a £500 million new train fleet at Ealing at around 10pm on Tuesday.

Engineers worked overnight to try to resolve the issue by installing new wires before trains resumed on Thursday.

In the early hours, National Rail said a near-normal service had resumed, with some alterations on commuter services in the Thames Valley area, including trains serving Maidenhead and Twyford.

One of the four train lines is expected to be closed to electric trains during the evening rush hour.

Great Western Railway (GWR), Heathrow Express and TfL Rail services were all affected on Wednesday.

Two of the four lines usually used were opened at around 12.40pm after engineers cleared debris and restored power so trapped trains could be moved, but Network Rail, the Government-owned company responsible for managing Britain’s rail infrastructure, could only perform repairs while trains were not running.

The damage was caused by a high-speed Class 802 Hitachi train which was being tested between London and Bristol ahead of its handover to GWR.

Hitachi said a “full and thorough” investigation would take place to identify the cause of the issue.

Class 802 trains are bi-mode, meaning they can operate on electric and diesel power.

They take electricity from overhead wires using pantographs mounted on their roofs.

GWR is investing £500 million in a fleet of 36 Class 802s from Hitachi – part of an overall order of 93 from the Class 800 Series which are replacing the operator’s high-speed rolling stock by the end of next year.