HS2 viaduct begins crossing Birmingham rail lines
HS2 engineers have completed the first major phase of launching the Duddeston Junction Viaduct over the Birmingham to Derby railway lines, marking the start of a complex operation to cross six live railway tracks.
The 705-metre-long structure is the first and longest of five interconnecting viaducts forming the Curzon Approaches, which will carry HS2 into Curzon Street Station through Birmingham’s industrial heartland.
The first 170 metres of the viaduct has now been launched over two freight lines that carry goods into the city.
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The wider operation will eventually see the structure cross three freight and three passenger lines, with completion of the crossing operation expected next summer.
The next phase, which will involve crossing the passenger railway lines, is scheduled to begin in December.
HS2 viaduct crosses six live railway lines
Duddeston Junction Viaduct presents a series of engineering and construction challenges due to its geometry and constrained location.
The structure follows a varying horizontal curve and rises on a three per cent gradient to reach around 12 metres above the existing railway. It is being constructed within a narrow site between six live railway lines and a busy industrial estate.
Tony Zakaria, HS2’s Senior Project Manager for the Curzon Approaches, said: “Launching the fifth and final viaduct on the Curzon Approaches is a clear sign of the progress we are making to bring high speed rail to Birmingham.
“This final mile stretch of the HS2 route into the city centre is extremely challenging and we’ve worked exceptionally hard, in conjunction with Network Rail, to plan the whole operation with minimum disruption to both passenger and rail freight services”.
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Balfour Beatty VINCI (BBV), HS2’s construction partner, began preparation works for the viaduct in 2023. This included relocating major utilities, addressing ground contamination and diverting two of the three freight lines onto a new bridge and embankment.
BBV constructed the Duddeston Mill Road Underbridge before working with Network Rail to realign the two freight lines. The new arrangement created a 20-metre-wide corridor between the existing lines, providing the clearance required for the HS2 structure.
Up to 90 operatives and engineers are working on the project within the constrained site.
6,835-tonne steel viaduct assembled in seven spans
The weathering steel viaduct comprises 14 spans, each approximately 55 metres long, with the complete structure weighing up to 6,835 tonnes.
Seven spans will be assembled and launched across the railway. Each completed span is added to the rear of the structure before the viaduct is pulled forward using a sliding technique.
Once the structure has cleared the railway lines, the remaining seven spans will be lifted and lowered into position by crane on the opposite side of the railway.
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The viaduct will be supported by one abutment, two steel piers, four portals and eight concrete piers. At 705 metres, it will be more than twice the length of the approximately 300-metre Curzon 1 viaduct.
Ross Rendell, Section Manager at Balfour Beatty VINCI, said: “Duddeston Junction Viaduct is hugely complex and a key section of the HS2 route that will take trains in and out of Curzon Street Station.
“The 705-metre-long structure is being built inside a narrow space next to a live railway, where it curves above Birmingham’s industrial heartland at an incline.
“The viaduct also crosses over six railway lines, adding further challenges to its construction. I’m incredibly proud of the way my team has overcome these hurdles, as this huge viaduct continues to take shape.”
HS2 and BBV are now working with Network Rail to plan the next stage of construction, which will see the viaduct cross the passenger railway lines.
The Duddeston Junction Viaduct forms part of the wider HS2 route through inner-city Birmingham. The route will emerge from Bromford Tunnel before travelling through a cutting at Washwood Heath and ascending through Saltley towards the viaduct.
Once complete, the structure will provide the clearance needed for HS2 to pass approximately 12 metres above the six railway lines below.
