Why tunnels work

Tunnelling is becoming a preferred innovative solution as cities around the world look to expand their transport networks. They are very useful in locations where aboveground options are exhausted and society places a high value on land at ground level.

Tunnels allow for effective, secure train operations and offer a viable alternative to an aboveground rail system. They save space and reduce cost.  They also reduce the potential environmental impact on existing residential and business areas, when compared to aboveground options.

Construction of tunnels

The most significant construction site will be near the main tunnel portal at Forrestfield. This area will feature the site office and key infrastructure that will be used during the construction period, and 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.   

A number of cross passages will be constructed between the tunnels are various points. These allow people to move between the tunnels in the case of an emergency so they can make their way to the nearest emergency exit.


The length of the TBMs


The number of pre-cast concrete segments