HS2 structures take shape across rivers, wetlands and floodplains. The three Solihull viaducts

HS2 engineers have completed three major viaduct structures in Solihull, marking further progress on the West Midlands section of Britain’s new high-speed railway. The completed structures are Balsall Common Viaduct, Marsh Farm Viaduct and River Blythe Viaduct, all located on the southern approach to Interchange station.

The River Blythe Viaduct is the largest of the three and sits around 1.5 miles from Interchange station. Engineers are now preparing to install the final parapets, followed by acoustic barriers and waterproofing works. Marsh Farm Viaduct was the first to reach completion in summer 2025, while the main structure of Balsall Common Viaduct was finished earlier this year, with all parapets expected to be installed by spring 2027.

Together, the three viaducts show how HS2 is threading major railway infrastructure through a varied landscape of villages, wetlands, watercourses, floodplains and environmentally sensitive areas.

The 495 m River Blythe Viaduct crosses the River Blythe, its floodplain and Meriden Road near Hampton in Arden. Because the river is designated as a Site of Special Scientific Interest, the structure was designed to reduce environmental and visual impact. Its low-lying deck, around 12 m above the ground, is supported by two abutments and 19 concrete piers.

The Y-shaped split piers reduce concrete volume while softening the appearance of the structure. The space beneath the viaduct also maintains ecological movement routes for species including badgers, bats, birds, fish, great crested newts, otters and water voles. This is important because viaducts across sensitive landscapes should avoid becoming barriers to wildlife movement and floodplain function.

Two and a half miles south, Marsh Farm Viaduct carries the HS2 main line over Bayleys Brook and surrounding marshland. At 145 m long and just 5 m above ground, it is the smallest of the three. During construction, it is also being used as a haul road to support nearby embankment and cutting works, helping reduce lorry movements on local roads.

Balsall Common Viaduct is 430 m long and 8 m high. It crosses Station Road, Truggist Lane, Bayleys Brook, the Heart of England Way and the associated floodplain. The structure sits near the existing Network Rail line and close to the village of Balsall Common, making community input an important part of the final appearance.

Local residents helped choose the parapet design, including a polished finish intended to reflect the sky and surrounding vegetation. The viaduct will also feature a weave motif, referencing the area’s textile history.

The works also required careful watercourse management. Engineers realigned a 150 m section of Bayleys Brook so that Balsall Common Viaduct could pass above it, demonstrating how railway structures often depend on coordinated civil, hydraulic and environmental design.

HS2 will include more than 500 bridging structures, including over 50 major viaducts with a combined length of about 15 km. The completion of the Solihull trio is therefore one local milestone within a much wider programme, but it also shows the level of design detail needed where high-speed rail crosses communities, roads, rivers and protected landscapes.