The Sunbury line generally traverses flat country and thus has no major earthworks, except on the west bank of the Maribyrnong River where it requires some moderately heavy earthworks. It has eight level crossings and several bridges under or over roads.
Usually stops all stations except South Kensington. Some daytime services originate and terminate at Watergardens. Some weekday peak services run express between North Melbourne and Sunshine, stopping at Footscray. Early morning weekend services skip Southern Cross and South Kensington. Weekday morning and weekend services run clockwise, while weekday afternoon services run anticlockwise, through the City Loop. Early morning weekend services run via Southern Cross to and from Flinders Street.
History
Origins
The Melbourne and Murray River Railway had been built out as far as Sunbury by February 1859.
1921–2002: The St Albans line
of the line to St Albans was done in October 1921, although electrification occurred to North Melbourne in May 1919 as part of the Essendon electrification and to Footscray in August 1920 as part of the Williamstown electrification. North Melbourne to South Kensington was quadruplicated in 1924, and South Kensington to Footscray in November 1976. Automatic block signalling was provided between South Kensington and Footscray in August 1927, from Footscray to West Footscray in October 1927, North Melbourne to South Kensington in June 1928, Sunshine to Albion in July 1929, West Footscray to Sunshine in October 1929, and Albion to St Albans in February 1930, thus resulting in the entire electrified line being provided with this signalling.
2002–2012: The Sydenham line
Electrification and automatic block signalling were extended to Sydenham, opening on 27 January 2002: as such the St Albans line was renamed the Sydenham line. A new station was built in northern St Albans, called Keilor Plains, as part of the electrification project as well as a newly revamped station at Sydenham, Watergardens. In early 2012, the Sydenham line was found to be one of Melbourne's five worst lines for overcrowding.
2012 onwards: The Sunbury line
On Sunday, 18 November 2012 the electrification of the line to Sunbury became operational; as a result, the Sydenham line was renamed the Sunbury line. Metro's electric train service now continues on from Watergardens station, first to Diggers Rest and then to its new end terminus at Sunbury station, though many services continue to terminate at Watergardens. New passenger services were added on the same date across the whole line and weekly rail services for Sunbury in particular were boosted from 298 to 489. The $270 million electrification project was first proposed in the 1969 Victorian transport plan, but was opposed by some Sunbury and St Albans residents over concerns of less comfortable travel and added congestion at level crossings on the route as a result of increased services.
In 2015, work commenced on the Metro Tunnel, a rail tunnel through the Melbourne CBD between the Sunbury line at South Kensington and the Dandenong corridor at South Yarra. On completion, the Sunbury line will be merged with the Dandenong lines and operate as an end-to-end service through the tunnel. Work to extend platforms and upgrade traction power, in order to enable the operation of High Capacity Metro Trains on the Sunbury section of the new line, was funded in 2019. The works will include power and track improvements to trains travelling through the Metro Tunnel, overhead electrification works between Sunbury and South Kensington and at South Yarra, signalling power upgrades and additional infrastructure at Calder Park sidings. The works are being designed by Aecom and undertaken by CPB Contractors and John Holland Group.