Customer: Transport for NSW

Contract: Construct Only

Location: Penrith, New South Wales




Project Capabilities

Civil Rail Roads & Bridges

 Fast Facts

  • Castlereagh Road railway bridge replacement
  • First complete bridge (abutments & deck) moved into position
  • 1,476 m3 of PCP concrete poured
  • 5,067m3 of leanmix concrete poured
  • 2,412m of stormwater drainage installed


The Mulgoa Road, Penrith upgrade is vital to connect road users to the Penrith CBD, Blue Mountains and surrounding suburbs. The upgrade includes widening Castlereagh Road and Mulgoa Road to 3 lanes in each direction, upgrading High Street and Mulgoa Road intersection as well as Castlereagh Road and Jane Street intersection, constructing a new railway bridge over Castlereagh Road, increasing turning lane capacity and upgrading pedestrian and cycle paths.

Working within the main road corridor of Penrith which connects to the Blue Mountains, Windsor and the Penrith CBD has required us to implement multiple weekend road closures of Castlereagh Road in order for us to minimise disruption to the local community and road user and to complete works in a shorter timeframe.

This was especially true when it came to the installation of the new railway bridge over Castlereagh Road. The original road alignment that passed under the bridge was 4 lanes wide and in order for us to widen the road to accommodate 7 lanes, we had to construct and install a new railway bridge.

The reference design nominated a sequential construction method where the 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 Roads and Maritime Services (RMS) 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 Project requires us to upgrade the Castlereagh Road and Jane Street intersection which we are unable to be completely shut down due to the heavy traffic flow and connectivity to other areas of Sydney. To overcome this obstacle, we saw an opportunity to close Castlereagh Road and minimise capacity at the intersection for 9 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 Jane Street.

Being able to successfully execute multiple road closure weekends throughout the entire project has not only positively impacted our program, but also enabled us to minimise disruption to the community and road user.

McConnell Dowell are on track to complete the Mulgoa Road, Penrith Upgrade by mid-2021.

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