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. The two main sections, SRL East and SRL North, are planned to form a single 60 km (37 mi) fully automated orbital metro line through the city's middle suburbs, with 13 stations between Cheltenham and Melbourne Airport connecting to eight existing Melbourne rail lines across four sections: SRL East, SRL North, SRL Airport and SRL West.

The SRL is a key part of Victoria's "Big Build" initiative, 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 largely radial with no connection 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 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 large cost.

Although the Victorian government signed the first $3.6 billion contract with the Suburban Connect consortium in December 2023 to build the tunnels, the state Liberal/National opposition remains opposed to the system. State Opposition Leader Brad Battin 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 and Shadow Infrastructure Minister Bridget McKenzie also vowed to scrap $2.2 billion in federal funding for SRL leading up to the 2025 Australian federal election, which they lost.