Specialist divers have poured around 900t of concrete to protect two major railway viaducts for Network Rail.
The work came after laser surveys revealed that fast-flowing water on the River Eden in Carlisle had caused parts of the riverbed to wash away, posing a risk to the foundations of two viaducts on the West Coast main line.
Trains have been running at reduced speeds of 20mph over the Victorian and 1940s-built structures because of the riverbed erosion.
Divers from Scour Protection helped to pour the concrete to provide a stable platform for the viaducts’ columns and piers. Water visibility in the River Eden is particularly poor, with a lot of the work done by touch alone. More than 2,200 tonnes of rock has also been placed in the river temporarily to calm the waters and divert its flow so the divers can work below the surface.
Once the first phase of work is complete in the next few weeks, trains will be able to run at full speed of 100mph over the viaducts.
Chris Pye, Network Rail infrastructure director for the North West, said: “It’s not every day you call in diving teams to help improve railway lines, but this work is essential to keep passenger and freight trains moving on the West Coast main line over the River Eden in Carlisle.
“After using the latest laser mapping technology to give detailed scans of the riverbed we brought this work forward so we could secure this crucial rail link between England and Scotland for the winter ready for the second phase of work next summer.”
The second phase of viaduct strengthening work will take place in summer 2022 as a permanent fix to the riverbed erosion.