Construction of tunnels
The most significant construction site for the Forrestfield-Airport Link will be near the main tunnel portal at Forrestfield. This area will feature the key infrastructure, including bentonite and slurry treatment plants, which will be used during the construction period to support the tunnel boring machines. The site will eventually be home to a new train station and car parking facilities.
Once the tunnel boring machines arrive, they will be launched from this site and will make their journey to Bayswater, constructing the tunnels along the way.
The tunnels are at varying depths with the deepest point being beneath the Swan River, where the roof of the tunnel will be approximately 25m below the riverbed. Overall, the depth of the tunnel will average 15m below the surface.
Cross passages (allowing access between the tunnels) and emergency exits will be constructed at various points along the rail route.