The route for the Airport Line 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 High Wycombe.
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 (ancillary buildings, car park and emergency muster point).
The ancillary buildings house communications, electrical and mechanical equipment and controls. They also contain air vents which will help ventilate the shafts and tunnels.
Works are most advanced at Abernethy Road EES, where the upper ancillary building – the building erected on top of the shaft – has been fully installed. Fit-out of the shaft is well underway and the adjacent stormwater basin has been built.
Installation of steel modules for the staircase and the landings at Airport West Emergency Egress Shaft (EES) are nearing completion. With the roof structure of the upper ancillary building already in place this concludes major steel works at the site. Up next, in January, will be roof sheeting and fit-out works.
The first quarter of 2021 will also change the face of the Wright Crescent EES site, with the planned removal of cranes freeing up space for earthworks around the shaft and building, including landscaping and permanent fencing.
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).
The final cross passage, located between Airport Central and High Wycombe stations, has been excavated and waterproof lining has been installed. Works are underway on the collars at the end of the passage
The majority of the cross passages has already been handed over to the fit-out team.