Network Rail continues work to prevent landslips on the Chiltern main line

Harbury embankment aerial view. Credit: Network Rail

Since December 2019, a £9 million investment by Network Rail has seen engineers working to stabilise the slope on the south side of Harbury tunnel between Leamington Spa and Banbury. Historically the area has been beset by earth movement, most recently in early 2015 when a 300,000-tonne landslip on the other side of the tunnel closed the Chiltern main line for six weeks.

Joel Farrell, Scheme Project Manager at Network Rail, said: “The ground here, made up of layers of limestone and shale, can be unstable and could potentially cause issues for the railway running through it. This preventative work will stop any future slips and make it much more secure.”

The geological makeup of the earth at Harbury means landslips and subsidence have caused issues for the railway since its completion in 1852. 

The first attempt to make the slopes of the cutting at Harbury shallower to prevent landslips was undertaken by Victorian engineers of Great Western Railway in 1884.

Now, 136 years later, this work continues as the Victorian’s modern-day counterparts continue to stabilise the embankment making it less steep and pinning it with large nails and piles to make it more stable. A new retaining wall will also be built at the bottom of the slope to prevent soil movement.

The project has been carried out during the daytime while passenger and freight trains continued to run below, meaning no disruption to services and no noisy overnight work.

The embankment strengthening began in December 2019 and is expected to finish in 2021.