The project represents the largest upgrade of public transport in Melbourne since the creation of the City Loop tunnels more than 40 years ago.
It has created substantial new capacity for rail services in inner Melbourne, effectively freeing up rail capacity in the existing City Loop tunnels and providing a new tunnel that doubled the capacity of the City Loop.
The Rail Systems Alliance Work Package involved the installation of 55 kilometres of high-capacity signalling on the Sunbury to Cranbourne/Pakenham line that runs through the Metro Tunnel. It also required the design, supply and installation of power and operational control systems, conventional signalling, and platform screen doors at the five metro stations.