The railway between Didcot Parkway and Oxford will not reopen until early June following the closure of Nuneham viaduct in Oxfordshire for safety reasons on Monday 3 April, as Network Rail engineers work around the clock to repair the structure. 

The line was shut after Network Rail installed monitoring equipment detected increasingly significant movements of the viaduct, which crosses the River Thames between Culham and Radley, despite Network Rail carrying out stabilising works in recent weeks. Monitoring equipment is routinely installed across the rail network to provide data on the infrastructure and detect when any issues may arise. The structure had been monitored with such equipment since 2018, with extra equipment installed earlier this year. Prior to the recent rapid deterioration of the viaduct, its condition posed no risk to trains or passengers.

The viaduct, like other rail infrastructure, undergoes regular inspections, including with divers below the water every three years. Manual inspections have been carried out at the viaduct every three months since 2021, with full inspections of the stability of the southern bridge support structure in 2019 and 2022. These inspections led to a planned low intrusive ground stabilisation scheme in March 2023.

Unfortunately, these interventions in March 2023 were not successful, resulting in the closure of the line once the condition of the viaduct rapidly and unexpectedly deteriorated. The cause of the rapid decline in the condition of the southern support structure is currently unknown, however engineers will be in a better position to assess this once the old support has been removed.

Engineers have been working around the clock since the line was closed and are now working to replace the southern support structure with a new one, which will provide a long-term fix and allow for both passenger and freight trains to run again between Didcot Parkway and Oxford by Saturday 10 June. The work to replace the support structure will be complex and challenging owing to ground conditions at the site, including the proximity to the River Thames and the heavy clay soil in which the new support will need to be secured.

Network Rail has been working closely with its rail industry partners to help keep passengers moving while the line is closed. As part of this partnership, GWR, CrossCountry, Chiltern Railways and Network Rail have implemented a revised timetable for the duration of the line closure, with a rail replacement service and local shuttle services running.

Those travelling between London Paddington and Oxford/North Cotswolds will need to change at Didcot Parkway for replacement bus services, adding about 45 mins to journey times.

A non-stop bus shuttle will run between Didcot and Oxford, with another calling at intermediate stations. Trains will continue to operate largely as planned between Hereford/Worcestershire and Oxford.

Stuart Calvert, Network Rail’s capital delivery director, said: “Our teams have been working 24/7 since the line has been closed to determine how best to repair the structure so that we can run trains across the viaduct safely once again.

“We can now confirm that we’re working towards a reopening date of Saturday 10 June and will be replacing the old southern support structure in order to start running trains safely again.

“We are sorry for the disruption this has caused for passengers and advise them to continue to check before they travel.”

Huw Margetts, CrossCountry’s regional director, said: “We’re sorry that passengers’ journeys will be disrupted until early June while Network Rail carries out this urgent work. The plans we introduced to help people keep travelling have worked well, and we will work closely with our industry partners to ensure this continues until the line reopens. Until then, we encourage anyone travelling to check their journey carefully before departing or visit our website for further information.”

Mark Hopwood, GWR’s managing director, said: “It is very disappointing to hear this key route will be out of action for some considerable time, but it’s important Network Rail are given the time to make the necessary repairs.

“We at GWR are working hard with our colleagues at CrossCountry and Chiltern to ensure we can give passengers as many journey options as possible and will continue to see what more we can do over the coming weeks to improve that situation.”