Melbourne Metro 2 (MM2), also known informally as Metro Tunnel 2 or Metro 2, is a proposed underground rail project in Melbourne, Victoria, Australia. It involves constructing new rail tunnels from Newport to Clifton Hill via the city centre. Conceived as a follow-up project to the under-construction Metro Tunnel (MM1), MM2 would link the Werribee line, and possibly also the Geelong line, in Melbourne's south-west to the Mernda and Hurstbridge lines in Melbourne's north-east.[1]
Likely to be split into two stages due to the project's large size and cost, the first (western) stage would include a new interchange at Newport, followed by two new stations in the Fishermans Bend development precinct and a new interchange at Southern Cross. A second (eastern) stage would extend to new interchanges at Flagstaff and Parkville, followed by a new station in Carlton or Fitzroy and a new interchange at Clifton Hill.[2]
Although MM2 has been proposed and refined by a number of government-led and independent reports and proposals, no funding or policy commitment to its construction is in place as of 2024[update].