A lineside fire has caused serious damage to signalling equipment and overhead electric wires in South Wales.

Network Rail is urging passengers travelling between Cardiff and Newport to check before they travel until the end of May. Overnight work by Network Rail’s engineers overnight has minimised disruption and electric trains are now running against as engineers have restored the overhead cables means electric trains can also run again.

Although the damage will still disrupt journeys by a few minutes, the progress made so far will help with transport to and from the Beyoncé concert at the Principality Stadium in Cardiff on Wednesday 17 May.

However, Network Rail has warned that the signalling equipment will take longer to fix and that minor disruption is likely to continue until the end of the month.

The fire was reported in the early hours of Monday, 15 May, at Marshfield, between Newport and Cardiff. The railway was shut immediately before two lines were able to reopen later that morning.

An investigation into the cause of the fire has begun.

Nick Millington, route director at Network Rail Wales and Borders, said: “We’re very sorry for the disruption passengers are facing between Cardiff and Newport following a fire which caused severe damage to signalling equipment and overhead cables.

“The success of our engineering teams overnight means disruption is now minimal – a few minutes per journey – and the restoration of the overhead cables means electric trains can also run again, which will be a big help before and after the Beyoncé concert in Cardiff, tomorrow night.

“As work continues to repair the signalling equipment over the coming weeks, we are urging passengers to please check before travelling with their train operator.”

Richard Rowland, Great Western Railway Customer Service and Operations Director, said: “We’re asking customers to check before they travel and allow more time for their journeys both before and after the concert.

“Safety of our customers is of the uppermost importance. Trains do get very busy and there will be a need to queue outside the station following the gig. Customers travelling from further afield are reminded to check the time of the last trains home.”

CrossCountry’s Regional Director, Huw Margetts, said: “We’re grateful to Network Rail colleagues for quickly getting the lines open again, which will be a big help to those going to Cardiff by train for the concert on Wednesday. However journeys may take a little longer, and with a limited service in the evening we’re asking everybody to check their journey home carefully.”

Elliott Swallow, Head of Current Operations at Transport for Wales, said: “We’re advising our customers to plan their journeys carefully for services in both directions between Cardiff – Newport as disruption and delays are expected as a result of the displacement of train crew and trains.

“This could result in reduced capacity on some services and while we’re working hard to minimise disruption as much as we possibly can, we’re expecting an impact on services until 24 May at the earliest.”