HS2’s tallest steel truss bridge enters final construction phase

HS2 has completed the structural assembly of Curzon 2, the tallest bridge on the new high-speed rail network, marking a major civil engineering milestone ahead of a complex launch operation. The 4,200-tonne structure, with a 24-metre-high truss, will be slid 180 metres into position over the Birmingham–Lichfield railway line in a carefully sequenced three-stage operation. Once locked into place, the tip of the arched truss will reach more than 40 metres in height.

Curzon 2 forms part of the Curzon approaches, a five-viaduct system that will carry HS2 trains into Birmingham’s Curzon Street Station. The bridge’s trussed superstructure consists of 670 steel sections welded into triangular units. It is built from weathering steel, which will naturally darken over time, and is intended to reflect Birmingham’s industrial heritage.

The constrained site significantly increased the complexity of the work. Positioned between the River Rea and the existing rail network, the project required 32 permanent piles, each around 30 metres deep, to strengthen the ground before construction began. The 150-metre deck was assembled on the seven piers of the adjacent Curzon 1 viaduct before the truss was erected, allowing the team to work within a restricted urban construction area.

The upcoming launch operation is a significant heavy civil engineering task. The bridge will first be pushed forward 50 metres during night works to avoid affecting passenger services. It will then be moved 93 metres over the Cross City line during a scheduled closure between Birmingham New Street and Lichfield Trent Valley from Friday 29 May to Sunday 31 May 2026. A final 37-metre push will dock and lock the structure into position on four concrete piers. High-precision hydraulic strand jacks will control the movement as the bridge slides over temporary bearings.

Beyond its scale, Curzon 2 demonstrates how bridge-launching methods can help reduce disruption to existing rail services while addressing severe spatial constraints in dense urban areas. Once complete, it will serve as a major structural element on the approach to Birmingham Curzon Street Station and a prominent feature of the city’s rail infrastructure.