Over nine days between 16th and 24th January 2021 the huge concrete box was pushed under the East Coast Main Line railway.
The prefabricated structure forms a new rail underpass at Werrington, north of Peterborough, to enable slower moving freight trains to dive underneath the passenger route and use an adjacent line northwards.
The time-lapse video footage below shows the 155-metre curved concrete box tunnel being pushed into place at just 1500 mm per hour using four hydraulic jacks.
This is the first time that a curved concrete box has been installed in this way in the UK.
Although the big push took nine days, the method avoided hundreds of hours of passenger disruption and meant that services could continue running throughout. [They were not to know, when planning this project, that Covid-19 would have substantially reduced passenger numbers anyway.]
Main contactor Morgan Sindall and its team removed three of the tracks, lifted the overhead wires and dug out spoil from the site. Once the tunnel was eventually underneath, they then put everything back in place ready for regular services to resume.
Morgan Sindall's team comprised:
- Mabey Hire
- M O'Brien Group
- Central Rail Systems Alliance
- Oliver Connell & Son
- Aarsleff Ground Engineering
- Bell Formwork & Civil Engineering Services
- Tony Gee & Partners
- Mott MacDonald
- Jacked Structures
- London Rock Supplies
- Robore Cuts
- EB7 Immersive
- Richard Allitt Associates.
Paul Rutter, route director for Network Rail’s East Coast Route, said: “Our teams have completed this challenging piece of engineering in a creative way, which also allowed a reduced train service to continue for those who still had to travel.
“I’m so proud that this project has shown itself to be one which is industry leading and that our teams have had the opportunity to use this new technique for the first time in the UK on one of the country’s most famous railway lines.”
The next stage of the project at Werrington involves work to install two new tracks inside the new tunnel and the associated signalling system, ready for it to come into use at the end of 2021.
The project is part of the £1.2bn East Coast Upgrade, for faster, more reliable journeys between London, the north of England and Scotland.