Oxford-Didcot line closure: All your questions answered

The bridge that crosses the River Thames between Culham and Radley shut on April 3 amid concerns that it was sinking.

Here is everything that you need to know about the closure.

Why is the Nuneham Viaduct closed?

The line closed after monitoring equipment installed by Network Rail detected increasingly significant movements of the viaduct.

The concerns surround the condition of southern bridge support structure.

The train company has described this movement as a ‘rapid deterioration’ of the bridge that previously posed no risk to trains or passengers.

Have any concerns been raised in the past?

According to Network Rail, monitoring equipment is installed routinely across the network which detects issues when they arise.

The viaduct has undergone regular inspections, including with divers beneath 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.

But this work failed, leading to the rapid deterioration of the bridge.

When is the bridge expected to reopen?

The bridge was initially shut for one day while engineers assessed the situation.

After this initial assessment it was announced that the bridge would remain shut until the end of April.

But on April 10, Network Rail admitted that the planned opening date for the bridge is actually June 10.

The company has said that engineers are working around the clock since the line was closed in order to get the rail line up an running again.

When asked why this date, a Network Rail spokesperson said: “Having extensively evaluated the situation, the best solution is to replace the old abutment, with a new one, which will provide a long-term fix.

“Previously we had discussed providing a temporary support, which would have allowed us to run trains at reduced speeds, but the time frame for a long-term fix was not much longer, so deemed the best solution.”

What does disruption for passengers look like?  

Those travelling between London Paddington and Oxford/North Cotswolds will need to change at Didcot Parkway for replacement bus services, adding about 40 mins to journey times.

Passengers travelling between the midlands and south coast will also need to use replacement bus services between Oxford and Didcot Parkway. 

There is a non-stop service between Didcot and Oxford and a separate service calling at the intermediate stations. 

How is freight being affected by the closure of the line?

A Network Rail spokesperson explained that multiple diversionary routes are currently being used.

They said: “We are diverting a lot of the freight traffic via Cheltenham, via London up the west coast and via the Chiltern Mainline, which means journey transit times are extended, but freight is still able to run whilst we carry out work to stabilise the viaduct, over the coming weeks.  

“We are still working through the extended train plan and will have more specific stats in the next couple of weeks.”