Editing City Loop (section)

{{Short description|Rail tunnel through the Melbourne CBD}}
{{about|the underground railway line|the surface-level tram line|City Circle Tram|the "city loop" in Sydney|City Circle}}
{{Use dmy dates|date=August 2023}}
{{Use Australian English|date=April 2022}}

{{Infobox rail line
| name                            = City Loop
| logo                            = {{ric|Melbourne|City Loop|size=100px}}
| image                           = Melbourne Central Platform 3.jpg
| image_alt                       = Platforms at Melbourne Central station on the City Loop, 2024.
| caption                         = Platform at [[Melbourne Central railway station|Melbourne Central station]] in the <br/>City Loop, June 2024
| yearcommenced                   = 1971
| open                            = 1981
| yearcompleted                   = 1985
| close                           = 
| linelength                      = 
| stations                        = 3
| tracks                          = 2 single bidirectional tunnels Flinders Street – Parliament<br />4 single bidirectional tunnels Parliament – Flagstaff<br />3 single bidirectional tunnels Flagstaff – Southern Cross
| owner                           = [[VicTrack]]
| operator                        = [[Victorian Railways]] (1981–1983)<br />[[Metropolitan Transit Authority (Victoria)|Metropolitan Transit Authority]] (1983–1989)<br />[[Public Transport Corporation]] (1989–1997)<br />[[M-Train|Bayside Trains]] (1997–2004)<br />[[Connex Melbourne|Hillside Trains]] (1997–2009)<br />[[Metro Trains Melbourne]] (2009–present)
| routes                          = [[Railways in Melbourne|All suburban lines]] except Frankston, Sandringham, Werribee and Williamstown line trains
| character                       = Underground
| stock                           = 
| connectinglines                 = 
| electrification                 = {{1,500 V DC}} [[overhead line|overhead catenary]]
| map                             = {{City Loop}}
| map_state                       = collapsed
}}

The '''City Loop''' (originally called the '''Melbourne Underground Rail Loop''' or '''MURL''') is a piece of [[rapid transit|underground]] [[commuter rail]] infrastructure in the [[Melbourne central business district|central business district]] (CBD) of [[Melbourne]], [[Victoria (state)|Victoria]], Australia.

The loop includes three underground stations: [[Flagstaff railway station|Flagstaff]], [[Melbourne Central railway station|Melbourne Central]] (formerly Museum) and [[Parliament railway station|Parliament]]. The loop connects to Melbourne's two busiest stations, [[Flinders Street railway station|Flinders Street]] and [[Southern Cross railway station|Southern Cross]], and together with the [[Flinders Street Viaduct]] forms a ring of four individual tracks around the CBD.

Eleven metropolitan lines of the [[Railways in Melbourne|Melbourne rail network]] run through the City Loop, organised into four separate groups, the Burnley/City Circle, Caulfield, Clifton Hill, and Northern groups. Each group has its own dedicated single-track tunnel, with trains running on balloon loops around the CBD. The Loop follows [[La Trobe Street|La Trobe]] and [[Spring Street, Melbourne|Spring Street]]s along the northern and eastern edges of the CBD's [[Hoddle Grid|street grid.]]

Although concepts for an underground railway had been raised since the 1920s, planning was not seriously progressed until the 1960s. The 1970 Melbourne Underground Rail Loop Act finalised the design and established an authority to oversee construction of the project. Tunnelling works began in 1972 and the Loop commenced operation in 1981 with the opening of Museum station, now Melbourne Central. The loop was fully complete in 1985 with the opening of Flagstaff station.

A new rail tunnel under the CBD, the [[Metro Tunnel]], is currently under construction to relieve pressure on the City Loop. Upon opening in 2025, it will see the [[Pakenham railway line|Pakenham]], [[Cranbourne railway line|Cranbourne]] and [[Sunbury railway line|Sunbury]] metropolitan lines removed from the loop.