UK: Deep inside an 850-metre concrete box in west London, HS2 has finished the six underground platforms that will start the railway’s journey from London to Birmingham — built from nearly 2,000 precast slabs assembled from both ends of the box until the two halves met in the middle.

Completed underground high-speed platforms at HS2’s Old Oak Common station in west London
The completed high-speed platforms inside HS2’s Old Oak Common underground station box. Photo: HS2 Ltd.

HS2 Ltd and its construction partner BBVS JV unveiled the three 450-metre-long island platforms, each with two platform faces, on Aug. 13, according to Rail Magazine. Railway Supply previously reported the completion of the station’s foundation slab and the start of platform installation as part of HS2’s 2025 progress report; this covers the platforms’ completion and unveiling.

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Built from both ends, meeting in the middle

The platforms sit inside an 850-metre-long, 20-metre-deep underground box that took two years to excavate. Construction began with 1.59-metre-high “invert” walls cast in situ, followed by 1,946 precast platform slabs — each measuring roughly 2 by 4 metres and weighing 4-5 tonnes — manufactured by Explore in Worksop, East Midlands, and lifted into place starting in April 2025. Crews built the platforms concurrently from each end of the box, meeting in the middle in three island-style blocks, with a void left below the platforms for electrical installations. New Civil Engineer, which visited the site the day before the unveiling, reported that construction teams had to work through the extreme heat Britain experienced in recent months.

What’s still ahead

A further eight ground-level platforms remain to be built for Elizabeth line, Great Western Main Line and Heathrow Express services — the latter’s future beyond 2028 is uncertain, as its current contract expires that year. HS2’s tunnelling contractor, Skanska Costain STRABAG, is due to break through the underground box’s west wall to connect the station to the Northolt Tunnel. The announcement does not specify a firm reopening or fit-out completion date for the six new platforms, and HS2’s own May 2026 update put the wider programme’s opening between 2033 and 2036.

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