Rail Projects Victoria has installed the High Capacity Signalling (HCS) Communications-Based Train Control (CBTC) system on the Cranbourne – Pakenham section of the Sunbury line in Melbourne, the first retrofit of such a system in Australia. The installation was realised by the Rail Systems Alliance, comprising CPB Contractors, Alstom, and Metro Trains Melbourne, under a contract awarded in December 2017. Currently, the system is used by 17 trains per day alongside the conventional signalling system. From the opening of the Melbourne Metro Tunnel in 2025, a combination of HCS and conventional signalling will be used, switching exclusively to HCS when trains travel through the tunnel to the five new underground stations. HCS allows trains to run at shorter intervals, improving service frequency and reliability. A new signal control centre was built in Sunshine, a suburb of Melbourne, to control the HCS and monitor Metro Tunnel services.
