Metro Tunnel

The Metro Tunnel, formerly known as Melbourne Metro Rail (MMR), is an underground heavy rail tunnel forming part of the metropolitan rail network in Melbourne, the state capital of Victoria and second-largest city in Australia. The tunnel consists of twin 9 km (5.6 mi) bores running northwest to southeast of Melbourne CBD between South Kensington and South Yarra, incorporating five new underground stations. It links the Pakenham and Cranbourne lines with the Sunbury line via an alignment beneath Swanston Street, forming a high-frequency cross-city rail corridor that bypasses Flinders Street station and the City Loop. A proposed new Airport rail line serving Melbourne Airport and a future connection to Melton are also planned to operate via the Metro Tunnel.

The Metro Tunnel project was managed by the Victorian Infrastructure Delivery Authority and was part of the Victorian Government's "Big Build" infrastructure initiative. The project was built for an estimated cost of A$12.8 billion. The project enables the operational separation of various existing lines on Melbourne's rail network and increase the capacity of the system to allow for more frequent services. The Metro Tunnel has communications-based train control and platform screen doors, both a first for Melbourne. In addition to relieving the peak-hour ridership pressure on the City Loop, the tunnel has also brought heavy rail services to the University of Melbourne, various major tertiary hospitals and health science research institutes in Parkville (collectively known as the Melbourne Biomedical Precinct), and the Royal Botanic Gardens, all of which previously relied on trams and buses for last-mile transit to and from railway stations.

The Andrews Government began planning the project in 2015. Initial construction works commenced in early 2017. Sections of the Melbourne CBD, including City Square and parts of Swanston Street, were closed to enable construction of the tunnel and stations. Tunnelling began in 2019 and was completed in 2021. Construction of the five new stations was mostly completed in October 2025. The Metro Tunnel opened to the public with an initial soft-opening branded the 'Summer Start' on 30 November 2025, with over 70,000 people visiting on opening day. Full service through the tunnel, marketed as the 'Big Switch' commenced on 1 February 2026. In celebration of the opening of the Metro Tunnel, all public transport services in Victoria were free on weekends from opening day until the commencement of the 'Big Switch' on 1 February 2026.