As part a nine-day operation, an 11,000 tonne 155m curved box structure was pushed into place under the East Coast Main Line (ECML) last week as part of the successful completion of the latest stage of the Werrington Grade Separation project, part of Network Rail’s £1.2b East Coast Upgrade. The ‘box push’ was completed on Friday afternoon and the tracks and overhead lines reinstated over the weekend ready for the first train service on Monday morning (25 January). The scheme will alleviate congestion on the ECML, by removing conflicting at-grade freight train movements.
Tony Gee designed the permanent portal and tunnel approach structures as well as the temporary works for jacking of the portal, working alongside Mott MacDonald for Morgan Sindall Infrastructure.
The Jacked Portal structure was constructed off-line and pushed into position, along Slide Tracks which were constructed inside 3.21m diameter tunnels. The design included a hydraulically linked lateral guidance system to move the Portal around the plan curvature while also resisting out of balance horizontal soil pressures during the push. This is the first time that a curved Portal has been jacked in this configuration in the UK and ensured that long closures of the railway line were avoided.
Key points of the project: