Working within the heart of Penrith to deliver this vital road upgrade, we collaborated with TfNSW and developed innovative construction and staging solutions that minimised disruption to the community and commuters.

The project scope included widening Castlereagh Road and Mulgoa Road to three lanes in each direction; upgrading intersections at High Street - Mulgoa Road and Castlereagh Road - Jane Street; constructing a new rail bridge over Castlereagh Road; and upgrading pedestrian and cycle paths.

The biggest technical challenge was the installation of the new rail bridge over Castlereagh Road. The original road alignment that passed under the bridge was four lanes wide and in order for us to widen the road to accommodate seven lanes, we had to construct and install a new railway bridge.

The reference design nominated a sequential construction method where the new rail bridge was intended to be constructed above live traffic beside the existing bridge location. The bridge was then intended to be slid into place following the demolition of the existing bridge during a five day occupation at Christmas 2019. Due to issues associated with the relocation of both known and unknown utilities, along with the potential safety and efficiency issues associated with the erecting of a bridge over live traffic, a decision was made in conjunction with our customer to consider an alternative construction and installation methodology.

To facilitate the installation of the bridge McConnell Dowell elected to use Self-Propelled Modular Transporters (SPMTs) that allowed the bridge to be picked up and driven into position. Due to the changed installation method McConnell Dowell worked with SMEC to ensure that the bridge would be able to withstand the forces that would be applied to it during installation that hadn’t previously been considered.

During the bridge construction McConnell Dowell worked in collaboration with a specialist utility company (Taren Group) to ensure that the utility relocation works were carried out in a coordinated and efficient manner. McConnell Dowell also utilised the international expertise of specialist SPMT provider Sarens to plan and execute the movement of the bridge.

Sydney Trains allowed us to complete this work over the Christmas period in 2019, giving McConnell Dowell six days to move the newly constructed bridge into place. The bridge replacement was a resounding success and a great achievement for McConnell Dowell and Transport for NSW.

The second biggest challenge was the upgrading of the Castlereagh Road and Jane Street intersection, which we are unable to be completely shut down due to heavy traffic flow and connectivity issues. To overcome this obstacle, we saw an opportunity to close Castlereagh Road and minimise capacity at the intersection for nine days from January 1 2021, while the traffic volumes were at their lowest. This allowed us to excavate the old road pavement and construct the new road pavement throughout the intersection, as well as along Jane Street.

Despite the constrained urban environment, we used a combination of smart technical solutions, strategically staged road closures, and proactive community engagement to minimise disruption and engender strong support for the project.

The video below shows the completed works.

Watch the bridge move.