Second TBM begins work on $1.86B Forrestfield-Airport Link

Tunnel boring machine (TBM) ‘Sandy’ has commenced its underground journey from Forrestfield for the $1.86 billion METRONET Forrestfield-Airport Link, following the launch of the TBM ‘Grace’ in July.

‘Sandy’ was launched from a 12-metre-deep drive structure at the site of the Forrestfield Station in Perth this week.

‘Grace’ began its two-year journey to Bayswater in July, where the 8.5-kilometre Link will spur off the Midland Line. It has travelled around 620 metres into the earth and is currently travelling around 20 metres per day.

The two TBMs will each tunnel eight kilometres under Perth Airport and the Swan River, linking new stations at Forrestfield, Airport Central and Belmont.

Western Australian Transport Minister Rita Saffioti says ‘Sandy’s’ commencement is another landmark on the “suburb-transforming” METRONET project.

“From now on, as the construction of the three train stations on the Forrestfield-Airport Link ticks on above ground, underneath the surface ‘Grace’ and ‘Sandy’ will be boring and reinforcing the foundation of the tunnels which trains will run through in only three years’ time,” she said.

Construction of diaphragm walls (which will house the station box structure) is now complete at Airport Central, and excavation of the soil inside the walls has begun. Diaphragm walls are also under construction at Belmont, and are about 70 per cent complete.

As the TBM cutter heads bore through the earth, the machines will also install about 54,000 reinforced concrete tunnel segments, and now that the two TBMs have launched, segment production has ramped up.

About 5,750 segments of the 54,000 needed to complete the tunnel structure have already been fabricated at a local Forrestfield segment facility.

“The new METRONET line will provide a 20-minute direct link between the eastern foothills and the CBD – as well as the wider public transport network – via the airport. About 2000 jobs will be created as part of the project,” said Federal Urban Infrastructure Minister Paul Fletcher.

“Grace is expected to break into the station box at Airport Central Station in early 2018, with Sandy following shortly after.”