Coastline resilience is crucial to a safe railway.
It's something we’ve been working hard to improve on the south coast in recent years.
Three years ago, Network Rail turned detective to tackle the challenge of fixing a storm-damaged seawall at Dover to better understand the condition of the area before the incident.
It came two years after a section of railway fell into the sea in Devon following stormy weather. We reopened this stretch of the railway for passenger services in just eight weeks.
At Christmas 2015, a huge storm damaged the seawall behind Shakespeare Beach in Devon and the railway above it. The damage stopped trains from running between Dover and Folkestone in the weeks following.
By February 2016, we had used a range of techniques to investigate the wall and the structure supporting the railway, including laser surveys from an unmanned aerial vehicle.
Network Rail has excellent records of many of its Victorian structures but the Southern Railway – which existed from 1923 to 1947 – did not keep many documents on the work it undertook at the site in 1927.
Engineers investigated the structure itself with bore holes and trenches, and combed through local newspaper archives and online videos for more information.
Steve Kilby, then senior programme manager at Network Rail, said at the time of the research: “We are the sixth company to own this stretch of railway since it was built in the 1840s, and the record-keeping of some of our predecessors means we are still finding out how this stretch of railway was built.
“So along with traditional engineering, one of the first things we did with this project was to research the history of the site to build up a picture of what happened here.
“What is rapidly emerging is that, while the original viaduct was well built, the work that was done in the 1920s was not what we would have hoped.”
What we found
The railway on Shakespeare Beach was originally raised on wooden trestles, with the waves breaking on the beach below.
In 1927, the Southern Railway constructed the seawall alongside it, leaving room for a new set of tracks. They then dumped many thousands of tonnes of chalk around the viaduct, encasing it and building the railway on top. This was how it stayed until the storm of Christmas 2015.
The project to rebuild the railway and part of the sea wall at Shakespeare Beach began immediately after the Christmas period and cost £39.8m.
- More than 90,000 tonnes of rock armour shipped to Dover by barge, arriving at the port and latterly on a barge anchored offshore.
- A railway rebuilt on a 235m viaduct supported by 138 columns, rock armour arranged along the beach to protect it and the cliff face behind it from the power of the sea.
- At its peak, more than 1,000 people worked on the project at Dover, with about 150 working on the beach works and the footbridge.