The Warrnambool line was originally built by the private Geelong and Melbourne Railway Company and opened on 25 June 1857, the line being sold to the Victorian Railways in 1860. The line was designed by English engineer Edward Snell, and built as a single track. The standard of engineering was called into question as the light timber bridges required extra maintenance and had a short life span, while the decision to build only a single track resulted in slow and infrequent trains. Travelers between Melbourne and Geelong continued to prefer the bay steamers across Port Phillip Bay, leading to diminished profits for the company. At a railway commission enquiry, Snell defended his approach as necessary to complete the work in time, with the expectation that the engineering works would be upgraded as traffic and revenue increased. The railway had the misfortune of a fatal accident on its first run. The company's superintendent - and a friend of Snell’s - was struck when leaning out of the train's engine as it approached a bridge. An inquiry cleared the company of any negligence. The line was progressively duplicated from the 1950s to the 1980s. The line was later extended south-west, to Winchelsea in 1876, Colac in 1877, Camperdown in 1883, Terang in 1877 and Warrnambool, Dennington and Port Fairy in 1890. This line is now closed beyond Warrnambool, with the last train leaving Port Fairy on 10 September 1977, hauled by B75, with the line officially closing on 12 September 1977. A branch line was built from Koroit to Hamilton, via Penshurst, in 1890. At the same time a short-lived connection was opened between Penshurst and Dunkeld. It closed eight years later. Branch lines were also constructed from South Geelong to Queenscliff in 1879, from Moriac to Wensleydale and Terang to Mortlake in 1890, from Birregurra to Forrest in 1891, from Camperdown to Timboon in 1892, from Irrewarra to Cressy in 1910, and from Colac to Alvie in 1923. A narrow gauge branch was also opened from Colac to Beech Forest in 1902, principally to carry timber, and was extended to Weeaproniah and Crowes in 1911. The branch lines began to be closed from the late 1940s, the Wensleydale line being the first in 1948, followed by the Forrest line in 1957, the Irrewarra line in 1953, the Alvie line in 1954, the Beech Forest line in 1962, and the Timboon line in 1988. In July 2012, the Minister for Public Transport announced that a new crossing loop would be constructed on the line at Warncoort, between Birregurra and Colac. Tenders were called for in August. The loop opened in April 2014. In 2017, the Victorian State Government announced upgrades to be completed by 2019 that allow VLocity railcars to travel to Warrnambool. These upgrades include new signalling, level crossing upgrades and a second track between Boorcan and Weerite, either side of Camperdown.
