Construction of tunnels
The most significant construction site for the Forrestfield-Airport Link will be near the main tunnel portal at Forrestfield. This area houses the key infrastructure, including bentonite and slurry treatment plants, which support the tunnel boring machines. The site will eventually be home to a new train station, car parking facilities and further transit-orientated development.
The tunnel boring machines were launched from this site in 2017 and are making their journey to Bayswater, constructing the tunnels along the way. The tunnels vary in depth along the route, with the deepest point being beneath the Swan River, where the roof of the tunnel will be approximately 26m below the riverbed. Overall, the depth of the tunnels 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.