Construction of HS2's tunnel network has now passed the halfway mark. This marks a major milestone for the UK's new high-speed rail link. The new high-speed rail line will provide faster and more reliable journeys and free up space for more local trains on the most congested part of the existing West Coast Main Line.
HS2 has now excavated two of its five twin-bore tunnels, with two more progressing well. The remainder of the HS2 route includes six cut and cover or 'green' tunnels totalling 5.2 miles and 70 cuttings totalling 44 miles, meaning that more than half of the route - around 76 miles - is underground in tunnels or cuttings, reducing visibility of the railway.
In total, high speed trains will pass through 27.4 miles of twin bore tunnels - almost a fifth of the 140 mile route. This means that HS2's fleet of tunnel boring machines (TBMs) will excavate and build a total of 54.8 miles of tunnels. New analysis shows that 29 miles - 53% - have been excavated and constructed so far, dwarfing the length of tunnels being excavated for Crossrail under London.
Each TBM is advancing at an average rate of 12 to 16 meters per day, excavating the tunnels, lining them with precast concrete tunnel segments, and grouting them in place. Once the drives are complete, HS2 will move on to the next phase of the tunnelling project, when other key features such as cross-passages, ventilation shafts, and portals will be completed. This is ahead of the internal installation of the railway systems, including power, track, and signalling, which will allow high-speed trains to operate.
“We’ve still got a lot of work to do on the tunnels, including all cross passages, vent shafts and then fitting them out with the critical rail and power systems that will eventually allow trains to safely operate,” commented Jackie Roe, HS2’s Civils Delivery Director.
