Increasing capacity on the East Coast Main Line with a pioneering new tunnel
As part of our £1.2billion East Coast Upgrade, we’re increasing capacity for passenger trains on the East Coast Main Line by building a new two-track railway line that dives under it at Werrington, north of Peterborough.
The fly through video below visualises how the new dive under will look when in operation.
What are we doing?
The new line will remove constraints to the timetable caused by slower freight trains on the Great North Great Eastern (GNGE) route having to cross over the high-speed East Coast Main Line.
The new dive under provides an alternative route by enabling the new two track railway to run underneath the East Coast Main Line instead, separating it from any high speed passenger traffic.
The project has several phases and associated key milestones, the first of these milestones is the Stamford Slews.
The Stamford Slews relocated the two Stamford Lines approximately 30 metres to the west, creating the space between the Stamford Lines and the East Coast Main Line needed to allow construction of the southern dive under ramp.
The Stamford Slews phase of works was completed in early January 2020, with critical disruptive works achieved over the Christmas 2019 period.
Works included 3,580m of new track, associated overhead lines, signalling and telecoms as well as a significant number of enabling stages:
Cock Lane Footbridge
Replacement of the existing Cock Lane Footbridge with a wider span to accommodate the new alignment of the Stamford Lines. The new footbridge also included ramps, making the structure compliant with the Equality Act 2010.
The footbridge opened in November 2019.
Brook Drain River
840m re-alignment of Brook Drain river, north of Cock Lane Footbridge, to accommodate the build of the new Stamford Lines.
The newly aligned river has been designed to help with local flooding issues.
The design also features riffles – shallow sections of water – and side pools, where aquatic wildlife can take refuge during storm surges. Soft bank ledges have also been installed to help vegetation grows, with existing vegetation transferred to help maintain a habitat for the rare Four Spotted moth on the riverbank.
The diversion of a further 500m section of Brook Drain river, south of the new footbridge was also required.
This location was constrained by running parallel to 132kV overhead power lines and a large commercial estate. The designed solution enabled the new Stamford Lines to sit on top of a cast in situ concrete box culvert which carries the relocated river.
The position of the old Hurn Road clashed with the proposed route of the new Dive-under Lines. In order to progress works, the project worked closely with Peterborough City Council to agree a new route for Hurn Road, which would makes way for the new Dive-under Lines, whilst continuing to provide access and egress to the properties along the old Hurn Road.
Works to Hurn Road were completed in late 2019, allowing works to construct the north dive under ramp to continue.
A temporary 61 metre footbridge has been installed alongside the existing Lincoln Road Bridge.
This temporary structure, installed in late Autumn of 2019, will allow users of the existing bridge, including a number of utilities, to be temporarily diverted across the new structure.
Whilst the temporary Lincoln Road Bridge is used, works will be able to commence with installing an additional span to the existing Lincoln Road Bridge, which will allow the new Dive-under Lines to run underneath it.
Once works are complete, all users will be able to use the extended existing bridge again.
Milestones in progress
Despite national lockdowns due to COVID-19, work has progressed well. Changes to working procedures and processes, as well as some innovative thinking has allowed our colleagues to continue to work safely throughout lockdowns:
Lincoln Road Bridge
Whilst the temporary Lincoln Road Bridge is in use, works have continued on the installation of an additional span to the existing Lincoln Road Bridge, which will allow the new dive-under lines to run underneath it.
All the necessary piling has been completed the new bridge beams swung into place and services are in the process of being diverted into their final position..
Once all works on the existing Lincoln Road Bridge are complete, the temporary bridge will be removed and the newly-extended bridge will be open to pedestrians, cyclists and horse riders.
The north ramp has been constructed by installing 183 x 18 metre-long, 900mm diameter, rotary bored contiguous piles and over 900 x eight to 10 metre-long soil nails, finished with sprayed concrete facing. In total 120,000m3 of soil and clay has been excavated to create one of two 940 metre ramps.
Final fit out of the north ramp commenced following the ‘curved box’ structure being pushed in to position in January 2021.
In February 2020, our tunnel boring machine, named ‘Chloe and Georgia Whiteman’ after the daughters of Mark Whiteman, a colleague, who tragically passed away unexpectedly in 2019, was launched into the ground to begin the work of boring two three and a half metre diameter, 168 metre-long guide tunnels underneath the operational railway.
Thanks to the state of art remote track monitoring equipment which constantly measured the position of tracks, tunnelling was successfully completed, unnoticed by the trains passing above, at the start of August 2020.
The tunnels were fitted out with the required slide and guide plates inside to support the pushing of the ‘curved box’ into position under the East Coast Main Line.
South Ramp and South Dive Under Entrance
Mirroring the north ramp, a second 940 metre ramp is being constructed to the south of the dive-under, in the enlarged area made by the slewing of the Stamford Lines.
The Reception Pit, which was used to receive and recover the tunnel boring machine from the ground, was completed in April 2020. Works included the installation of 66 x 18-meter-long bored contiguous piles and the excavation of over 2,000m3 of soil and clay.
Piling for the South Ramp was completed in August 2020, which has now allowed excavation of the ramps to commence.
The South Ramp consists of 693no. 900mm diameter, bored contiguous piles up to 18m in length, and a further 340 metres of 10 metre sheet piles.
By relocating the Stamford Lines at an earlier stage has enabled the South Ramp to be constructed with no impact to the operational railway or passengers.
From March 2020 work began to build the dive-under structure.
The ‘curved box’ was built next to the East Coast Main Line in nine, interconnected sections. The structure is 155m long, 9.5m wide and 5.1m high, with 1m thick walls and soffit.
It weighs just over 11,000 tonnes, with is 1,000 tonnes heavier than the Eiffel Tower!
The ‘curved box’ was pushed under the East Coast Main Line using large jacks to propel and steer it during January 2021.
A trial push took place in December 2020, when the box was pushed forwarded by 16 metres to allow the structure to be weighed, the centre of gravity to be identified and all equipment to be calibrated and checked.
Over Christmas 2020, a bespoke signalling solution was installed and tested on the two ‘Stamford’ tracks running alongside the construction site. This work enabled a partial train service to continue to run on the East Coast Main Line while the tunnel was being pushed into place in January 2021.
The big push
During a nine-day partial closure of the East Coast Main Line in January 2021, the 11,000 tonne, 155-metre curved concrete box tunnel was pushed into place.
Time-lapse footage below shows the 11,000 tonne curved concrete box being pushed under the East Coast Main Line..
Whilst hydraulic jacks at the rear pushed the tunnel portal forwards at just 150cm per hour, excavators at the front broke away the guide tunnels to reveal the glide plates to guide and steer the tunnel into position.
This is the first time that a curved concrete box has been installed using this industry-leading engineering technique in the UK.
Teams 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.
There are two further phases planned for this project.
All four connections from the existing Spalding Lines to the future Dive-Under Lines were installed in Autumn 2020. Building of the foundations for the new Dive-Under Lines, which will eventually tie-in to these connections has commenced ahead of rail installation in Summer 2021
On the Stamford Lines, advantage was taken of the quiet Christmas 2020 period, by undertaking significant track renewal work on the Stamford Lines. The successful completion of this work will enable the final realignment and tie-in of the Stamford Lines to take place over only two weekends during June and July 2021, minimising passenger disruption.
Following completion of all previous phases, the final phase of works will be the installation of the final track formation, track drainage and track which will form the new Dive-under Lines and the new Stamford Line.
At the same time, the temporary Up Stamford Line will be removed.
The new Werrington Dive-under lines will be ready for use from late 2021.
Keeping you informed
Keeping you informed
This project is one of the most significant on the East Coast Main Line and involves major construction activity that has the potential to be disruptive to residents and businesses at specific points in time. We will continue to everyone affected in advance of this type of work.
Unfortunately, the series of community events have been cancelled due to Covid-19. We endeavour to re-start these as soon as possible. We are sorry for any inconvenience caused.