HS2 Completes 320-Metre M6 Viaduct in West Midlands

BIRMINGHAM, UK – HS2 Ltd and delivery partner Balfour Beatty VINCI finished positioning the second M6 South viaduct deck near Chelmsley Wood on Saturday, 24 October. Engineers pushed the 76-metre final segment of the 4,750-tonne west structure across the M6 motorway in nine hours using strand jacks while traffic ran underneath. The milestone establishes both 320-metre parallel viaducts across junction 4/4a, connecting tracks toward Birmingham Curzon Street and northern rail corridors.

What Is the Full Scope of This Project?

The M6 South crossing consists of twin 320-metre weathering steel viaducts spaced 100 millimetres apart on reinforced concrete piers.

The completed east deck, finished in 2025 following three incremental launch stages, will carry London-bound high-speed services calling at Old Oak Common and Euston. The newly positioned west deck was launched across four stages to support tracks toward Birmingham Curzon Street, Manchester, Liverpool, and Glasgow. Civil engineers utilised hydraulic strand jacks advancing at an average speed of 12 metres per hour to clear the carriageway without closing the main M6 motorway lanes. On-site activity will transition in 2027 toward the Coleshill triple-box rail-over-road structure, which will carry four HS2 tracks across the M42 motorway.

Key Project Data

How Does This Compare to Similar Projects?

The high-speed rail sector accounts for 47.60% of the United Kingdom rail market’s USD 108.15 billion valuation in 2025, driven by civil engineering packages of this scale (Source: Market Data Forecast, 2025).

Comparable data for this specific type of motorway bridge launch contract was not publicly available at time of publication. Across the broader network, the UK railway system sector is projected to expand at a compound annual growth rate of 4.3%, supported by long-term asset renewal and bridge maintenance frameworks (Source: Future Market Insights, 2025). The incremental slide over live traffic reflects civil engineering practices used on high-density high-speed rail routes in mainland Europe, where hydraulic jacking avoids protracted motorway shutdowns.

Editor’s Analysis

Executing incremental bridge launches above active strategic road networks limits traffic disruption penalties while keeping Phase One civil works on schedule. High-speed rail expansion forms nearly half of the UK’s total rail sector expenditure, making structural delivery milestones critical for maintaining supply-chain momentum (Source: Market Data Forecast, 2025). With focus shifting to the Coleshill triple box structure in 2027, Balfour Beatty VINCI’s methodology creates an operational blueprint for subsequent complex motorway crossings across the West Midlands.

FAQ

Q: What are the physical dimensions of the HS2 M6 South viaducts?
A: Both parallel viaducts measure 320 metres in length, stand 100 millimetres apart, and utilize 4,750 tonnes of weathering steel supported by concrete piers.

Q: What was the construction cost of the M6 South viaducts?
A: The specific stand-alone contract value for the M6 South viaducts was not disclosed by HS2 Ltd or Balfour Beatty VINCI.

Q: Did the viaduct launch cause major motorway closures?
A: Mainline M6 traffic continued moving while hydraulic jacks pushed the deck at 12 metres per hour, though the M42-M6 link road closed temporarily and reopened 25 hours ahead of schedule.