Speeds on part of the West Coast main line will be returning to 100mph after Network Rail and its contractors replaced the railway through a tunnel.

Shugborough Tunnel, just south of Stafford, was opened in 1847. As a result it was proving more and more difficult to maintain as it was designed in the days before container freight and high speed trains.

In order to keep the loading gauge - the size of trains that can fit under a railway structure - constant through the tunnel, Network Rail engineers and Amey Colas contractors dug out the track and ballast, renewed the drainage and replaced everything with new equipment.

More than 4,000 metres of new rail were put down, along with 2,300 sleepers, 7,200 tonnes of ballast and 1,000 metres of drainage between 9pm on Christmas Eve and 5am on January 2nd.

Steve Featherstone, Network Rail’s programme director, track, said: “There were some substantial challenges we faced with the work at Shugborough and it took six months of preparatory work, including diverting cables and digging trial holes, before we could start work.

“This was owing due to the age of the tunnel and the fact that detailed plans of the structure were not available

“I’m pleased to say that thanks to that preparation we achieved the work on time and we now have a fast and reliable railway again through Shugborough.”

The principle driver of the work was the change in rail freight over the years from heavy goods to containerised traffic. These trains are large and rectangular, while the tunnel was constructed as a complete oval (a Victorian technique for spreading the load equally). Despite modern techniques of tamping and lining, over time it became harder to maintain the gauge and required constant close monitoring and maintenance intervention.

The line will be retamped and lined before line speed operation resumes this month.