Four TBMs, rather than six, will be used to build the 16km of twin tunnels and the initial launch will be from a recycling facility in Clarinda instead of the nearby train stabling facility at Heatherton. These changes will reduce the impact of tunnelling on residents near the stabling facility.
Ground freezing will also be used to build most of the safety passages between the twin tunnels. This will reduce the need for large machinery above ground in residential areas, reducing disruption for residents and local road traffic by 90%.
Last year, the Tunnels South contract to build the twin tunnels between Cheltenham and Glen Waverley was awarded to Suburban Connect, a consortium of CPB Contractors, Ghella and Acciona Construction.
Tunnelling will start in 2026, and the line will open in 2035.
In April, expressions of interest opened for two contracts to deliver stations at Box Hill, Burwood, Glen Waverley, Monash, Clayton and Cheltenham.
