Suburban Rail Loop

The Suburban Rail Loop (SRL) is a rapid transit system currently under construction in Melbourne, the capital of Victoria and second largest city of Australia. The system is divided into four distinct sections (counterclockwise from southeast): SRL East, SRL North, SRL Airport and SRL West. The two main sections, SRL East and SRL North, are designed to form a single 60 km (37 mi) fully automated underground orbital metro line through the city's densely populated middle suburbs, with 13 stations between Cheltenham and Melbourne Airport connecting eight existing Melbourne rail lines and three major university campuses.

The SRL is a key part of Victoria's "Big Build" infrastructure initiative first proposed by the Andrews Government, aiming to make Melbourne the second Australian city (after Sydney) to build a fully automated rapid transit system. Several orbital rail schemes have been proposed and some constructed throughout Melbourne's history, but the rail network has remained radial with no peripheral connections among the existing railway lines. The Labor state government led by then-Premier Daniel Andrews announced the SRL as infrastructural policy in the lead up to the 2018 state election. Initial planning for the SRL was carried out in secret prior to its announcement, and, when the plans were released, it received significant attention. The SRL plan has been praised for its long-term vision and ambition, as well as being an innovative solution to the road congestions and commuting difficulties faced by Melbourne's transport network, but is criticised for its political motives, transparency of business case, prioritisation ahead of other transport projects, and huge cost.

Although the Victorian government signed the first $3.6 billion contract with the Suburban Connect consortium in December 2023 to build underground tunnels, the conservative opposition Liberal–National Coalition remains opposed to the project. Then State Opposition Leader Brad Battin (Lib) announced in January 2025 that he would halt further development of the SRL if he becomes Premier at the 2026 Victorian state election. Federal Opposition Leader Peter Dutton (Lib) and Shadow Infrastructure Minister Bridget McKenzie (Nat) also vowed to scrap $2.2 billion in federal funding for SRL leading up to the 2025 Australian federal election, which the Coalition lost in a landslide. As of September 2025, the construction of six SRL East stations is still underway, with tunnel boring machines to arrive and start digging in early 2026. Jess Wilson deposed Battin in a Liberal leadership spill in November 2025, with Wilson reaffirming the party’s opposition to the SRL and committing to halt all development of the project, including current construction, if she becomes Premier at the 2026 election.