Engineers working on designs to fix the sea wall at Dover have been investigating the history of the Victorian railway line.

Network Rail and its contractors Costain are conducting investigations into the wall and structure supporting the railway.

The Southern Railway which existed from 1923 to 1947 did not keep many documents on the work it undertook at the site on Shakespeare Beach in 1927.

Engineers have been investigating the structure itself, with bore holes and trenches, and combing local newspaper archives and online videos for information.

Steve Kilby, senior programme manager for Network Rail, said: “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.”

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 sea wall 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 Christmas Eve 2015, when two major storms lowered the beach level by two metres, and caused sink holes to appear alongside the wall. Since then the trains have been unable to run between Dover and Folkestone.

Since then, trains have been unable to run between Dover and Folkestone.

The tracks have been dug up to allow engineers to examine the nature of the soil under the railway.

Mr Kilby added: “We are working on designs all the time and the investigations we are undertaking will help us make the right decision for Dover. We need to be absolutely sure we have the right solution and a timescale we are confident in.”