The route for the Forrestfield-Airport Link includes 8km of twin-bored tunnels, with safe entry and exit points via underground stations at Redcliffe and Airport Central, as well as tunnel portals at Bayswater and Forrestfield.
Given the length of the tunnels, additional infrastructure is required between the stations to allow safe egress to the ground level in the event of an emergency, and access to the tunnels for maintenance.
As such, three emergency egress shafts (EES), twelve tunnel-to-tunnel cross passages and three tunnel-to-egress shaft cross passages will be constructed along the alignment.
View the cross passage and emergency egress shaft construction fact sheet.
View a map of all cross passage and emergency egress shaft locations.
Emergency Egress Shafts
What is an emergency egress shaft?
An EES provides access from the tunnels to ground level via stairs and lifts.
Its layout is designed in conjunction with the Department of Fire and Emergency Services to ensure functionality during an emergency situation.
It takes up to six months to build each EES and another six months to build the supporting ground level infrastructure (a two-storey portal building, car park and emergency muster point).
The portal buildings house communications, electrical and mechanical equipment and controls. They also contain air vents which will help ventilate the shafts and tunnels.
All three emergency egress shafts (EES) are fully excavated, and the respective base slabs have been poured.
Several flights of stairs were recently assembled outside the Abernethy Emergency Egress Shaft (EES) and then craned into the shaft in two sections. It is the first of three shafts to be fitted out with stairs and a lift frame.
At Airport West EES, excavation has been completed to connect the shaft to the two tunnels. This site is now being used to run ground freezing pipes from the cooling towers to the airside cross passages via Tunnel One.
At Wright Crescent EES, the erection of concrete precast panels for the lower section of the portal building, as well as installation of the steel roof sheeting, is now complete.
What is a cross passage?
A cross passage is a short concrete tunnel which provides a link between two main tunnels, or a link between a tunnel and an EES. It takes up to three months to build each cross passage, which are up to 10 metres long and five metres high (around three metres high after final lining installation).
Of the 12 tunnel-to-tunnel and three tunnel-to-egress shaft cross passages located along the alignment, five have now been completed.
Preparation works for the construction of the three cross passages located within the airside environment is ongoing. Ground freezing is underway for two passages, with excavation of Cross Passage Juliet nearing completion.
More information about the ground freezing method is available on the Cross Passage fact sheet.