HS2 Tunnelling Steelwork

Challenge

HS2 tunnel portals and shafts don't run to a normal construction sequence. Steel has to arrive and go in around a tunnel boring machine that is already moving, on a programme fixed months in advance. Miss a delivery window or get a tolerance wrong and the drive stops, or the wider works behind it slip. There was no scope for steel that was close enough — every portal frame and shaft support had to be fabricated to the tolerances the tunnelling design demanded, then sequenced onto site so it was ready before the drive needed it, not after.

Approach

MSR built the fabrication programme around the TBM, not the other way round. Delivery schedules were set against the tunnelling drumbeat rather than a standard site date, so steel left Bootle in the order the shaft and portal works actually needed it. Each piece was cut, welded and checked against tunnelling tolerances before it went near site, with sequencing treated as part of the fabrication job, not an afterthought handled on-site. That level of coordination is what MSR's Tier 1 contractor relationships on rail, marine and civil engineering work are built on — being trusted with the sequencing risk on a programme where the tunnel, not the fabricator, sets the pace.

Outcome

The steelwork went in without holding up the drive. Portal and shaft structures were fabricated and delivered to the tolerances and timing the tunnelling programme required, on a job where the margin for error was effectively zero. It's the kind of contract MSR is built for: not the biggest fabrication order on the books, but one where getting it right matters more than winning on price.