The Cranbourne line is a commuter railway line in the city of Melbourne, Victoria, Australia. Operated by Metro Trains Melbourne, it is the city's second longest metropolitan railway line at 44 kilometres (27.34 mi). The line runs from Flinders Street station in central Melbourne to Cranbourne station in the south-east, serving 24 stations via the City Loop, South Yarra, Caulfield, Oakleigh, and Dandenong. The line operates for approximately 20 hours a day (from approximately 4:00 am to around midnight) with 24 hour service available on Friday and Saturday nights. During peak hour, headways of up to 5 to 15 minutes are operated with services every 15-20 minutes during off-peak hours. Trains on the Cranbourne line run with a seven-car formation operated by High Capacity Metro Trains. The line originally opened in 1888 branching off from the Gippsland line at Dandenong as the South Gippsland line. Services operated as far as Port Albert, with extensive branch lines featuring on the non-electrified network. The line(s) were built to serve the regional townships of Cranbourne, Koo Wee Rup, and Leongatha, amongst others. The line was closed in 1993 after a decline in usage, however, the line was reopened and electrified to Cranbourne in 1995 as part of the "Building Better Cities" program. Significant growth has occurred since its reopening, with proposals to extend the line two stations to Clyde receiving support amongst other works on the corridor. Since the 2010s, due to the heavily utilised infrastructure of the Cranbourne line, significant improvements and upgrades have been made. A $1 billion upgrade of the corridor between Dandenong and Cranbourne is currently under construction, with improvements including the removal of all level crossings, rebuilding stations, and the duplication of of track. Other works taking place have included the replacement of sleepers, the introduction of new signalling technology, the introduction of new rolling stock, and other works associated with the Metro Tunnel project. These projects have improved the quality and safety of the line, and will be completed by the opening of the Metro Tunnel in 2025. History 19th century In 1888, the Cranbourne line (then known as the South Gippsland railway line) began operations, splitting off from the main line to Gippsland at Dandenong with an extension to Cranbourne. The line was progressively extended to Koo Wee Rup, Nyora, and Loch in 1890, Korumburra and Leongatha in 1891, and Welshpool, Alberton, and Port Albert in