The Western Harbour Tunnel Precast and Support Facility in Emu Plains has been purpose-built to manufacture and store the individual concrete segments and culverts which will line the section of the tunnels under Sydney Harbour.
These will be installed by the project’s tunnel boring machines (TBMs) as they excavate. More than 13,000 concrete segments and nearly 1,400 culverts will be custom made in Emu Plains before being transported to the tunnels.
Emu Plains site
The project started work to establish the Emu Plains site in March 2024 following the approval of the Modification to the Western Harbour Tunnel (WHT) project.
The site is within an existing industrial area off Railway Street in Emu Plains, to minimise the impact of work on the community and the environment.
During site establishment the project:
moved more than 538,000 cubic metres of earth
laid 1700 lineal metres of conduits for electrical cables and water lines
poured around 45,000 cubic metres of road base
poured around 27,000 cubic metres of concrete.
The Western Harbour Tunnel Precast and Support Facility in Emu Plains was officially opened in July 2025 by NSW Premier Chris Minns MP, NSW Minister for Roads Jenny Aitchison MP, Member for Penrith Karen McKeown MP, and Penrith Mayor Councillor Todd Carney.
Emu Plains Precast and Support Facility, August 2025
Before / After site establishment aerial of site
Precast and Support Facility
Precast concrete segments
As our tunnel boring machines (TBMs) excavate under Sydney Harbour they will fit together the walls, roof and floor of the tunnels with thousands of concrete segments being made at our precast facility in Emu Plains.
The massive segments are curved and specifically designed to line the tunnel in a ring-like pattern, as the TBM advances on its excavation.
Each one weighs 15 tonnes and 10 segments are used to form one ring of the TBM tunnel.
Around 50 segments are produced each day at Emu Plains. These are being stored at the site until they are transported by truck to the tunnels via the M4 and WestConnex to be used by the TBMs as they excavate under Sydney Harbour.
We will continue producing these segments over the next year for the TBM to complete the 1.5-kilometre section of the twin tunnels under Sydney Harbour.
A precast concrete segment is lifted to be taken to the storage area
Concrete culverts
Concrete box culverts are rectangular or square structures used primarily for directing water beneath roads, railways on other infrastructure.
In Western Harbour Tunnel they are being used to fill space in the bottom of the tunnel to reduce the amount of back fill needed and as a high voltage cable route below the future road pavement.
They will be installed by the TBMs in the floor of the tunnel as they excavate.
The culverts we are making at Emu Plains are bigger than the precast segments, weighing 20 tonnes each. They are being made using an innovative drycast method where a mix of dry concrete is compacted using high-frequency vibration and pressure to produce the culverts.
We have started producing an average of two culverts per day and we plan to produce nearly 1,400 concrete culverts over the next year.
A concrete box culvert cast at the Emu Plains facility
Jobs and skills training
The precast facility in Emu Plains creates around 700 jobs on the project, which has a target of employing 50 per cent women at the Emu Plains site.
We are running the Precast Skills Foundation pre-employment training program at Emu Plains that equips women with specialised skills to work at the precast facility.
This program has been developed by Western Harbour Tunnel contractor, ACCIONA, with Transport for NSW and the NSW Government Department of Education.
The Emu Plains site is expected to be operational for up to three years and has the potential for future reuse.
To find out more about training opportunities with Western Harbour Tunnel please contact us.
Precast Skills Foundation pre-employment training program
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