Skanska Costain Strabag (SCS)has completed excavation of HS2’s two 360m mined tunnels between the Victoria Road crossover box and Old Oak Common station box.
The breakthrough follows that of the northbound tunnel on October 13, creating a 14.2km link between Old Oak Common station and the West Ruislip tunnel portal in north-west London.
Work on the section began in May 2024. Excavators mined through London clay, removing 100,000 tonnes of material, before the tunnels were lined with 30,000m3 of sprayed concrete and then lined by cast in situ concrete using travelling formwork.
The construction method was driven by the tunnels’ engineering specification, which sees their width narrow from two tracks to one between the crossover box and station.
Both breakthroughs used a process not previously employed on HS2. The tunnel’s dividing wall was cut into blocks and pushed out from the station side back into the completed tunnel behind.
Completion of the tunnels links what will be London’s first HS2 station with other rail services. Old Oak Common will provide a rail hub where the high-speed line will connect with Great Western Railway, the Elizabeth Line and the Heathrow Express.
Old Oak Common will be one of the best-connected rail hubs in the country where the high-speed line, Great Western railway, Elizabeth line, and Heathrow Express will all converge, connecting communities and businesses to new opportunities across London, the West Midlands and beyond.
The TBMs that were launched from the eastern end of the Old Oak Common station box at the start of 2026 are continuing their 7.2km journeys towards HS2’s future central London terminus at Euston. They are expected to complete excavation in mid-2027.
HS2 Ltd chief executive Mark Wild paid tribute to the crews thatdelivered the breakthrough into the Old Oak Common station box.
“This is a key milestone for the HS2 programme and helps bring us a step closer to achieving our challenging ambition of delivering the railway from Old Oak Common to Birmingham Curzon Street by 2037, or earlier,” he said.
He added that HS2 was in the final stages of a programme reset to deliver the line at the lowest reasonable cost.
The Old Oak Common breakthrough follows what HS2 said is significant progress across the project. All deep bore tunnelling between London and Birmingham is complete, and more than 80% of major structures are under construction or complete. In 2025/26 HS2 Ltd said it delivered more than 10% more construction than planned and achieved six major milestones ahead of schedule.
