Black Cat Flyover Reaches Major Milestone as Skanska Completes Complex Steel Lift

Fifteen giant steel girders have been installed in a carefully choreographed operation at the Black Cat junction, bringing one of England's largest highways upgrades a step closer to completion.

Construction of the new Black Cat flyover has entered a significant new phase after Skanska completed the installation of the main structural steelwork that will carry traffic over the upgraded junction on the £1 billion A428 improvement scheme.

The operation saw 15 steel bridge girders lifted into position using a 650-tonne crawler crane, creating the primary load-bearing structure for the new flyover that will ultimately connect the upgraded dual carriageway through one of the country's busiest highway junctions.

The lift marks one of the most technically demanding stages of the project and paves the way for work to begin on the bridge deck and final structural connections.

Precision Lift Delivered in a Single Operation

Transporting the enormous bridge sections required police escorts before they arrived on site for installation.

The steelwork comprised:

• Ten 38-metre girders, each weighing approximately 60 tonnes, installed across the western and central spans.

• Five shorter girders, measuring around 18 metres and weighing 30 tonnes, positioned on the eastern section of the structure.

Due to the flyover's skewed alignment across the junction, engineers relied on temporary Megashore support towers to stabilise each beam during installation before permanent connections can be completed.

The temporary structures will remain in place until later this year, when the bridge becomes self-supporting.

Opening the Door to the Next Construction Phase

With the primary steelwork now complete, project teams will begin constructing the reinforced concrete bridge deck before permanently connecting the girders to the supporting piers.

The milestone also allows work to progress on another major element of the scheme—construction of the new underpass beneath the A1, which will form a key part of the redesigned junction.

Transforming One of England's Most Congested Junctions

The Black Cat junction forms the centrepiece of National Highways' wider A428 Black Cat to Caxton Gibbet improvement scheme, which will deliver approximately 16 kilometres of new dual carriageway between Bedfordshire and Cambridgeshire.

The programme includes:

• Two completely new grade-separated junctions

• Thirty-two new engineering structures

• Eighteen bridges

• A redesigned connection between the A1 and A428

Once complete, the project is expected to improve journey reliability, reduce congestion and strengthen east-west transport links across the region.

The new road is scheduled to open in spring 2027.

Keeping Traffic Moving During Construction

Despite the scale of the works, construction has largely been carried out while maintaining traffic on surrounding roads.

Skanska says detailed planning, carefully phased traffic management and daytime working have helped minimise disruption throughout the programme.

Foundation specialist Cementation Skanska delivered the extensive piling works supporting the flyover, operating up to four piling rigs simultaneously during the busiest stages of construction.

'A Landmark Achievement'

Neil Davison, Project Manager at Skanska, described the beam installation as one of the defining milestones of the project.

He said the successful lift reflected months of planning and close collaboration between Skanska's engineering teams, specialist subcontractors and supply chain partners.

The operation required multiple phases of traffic management and extensive coordination to create safe working areas while maintaining the flow of traffic around the live highway network.

With the flyover now taking shape above the Black Cat junction, the project has reached one of its most visible milestones to date, bringing the long-awaited transformation of one of England's most notorious road bottlenecks another step closer to completion.