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

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.

[1] The Epping and Hurstbridge lines stood alone from the rest of the network, having Princes Bridge station for their own exclusive use.

The one that was adopted was the building of a circular railway allowing trains to continue past Flinders Street, loop around and return to the suburbs.

In 1929, the Metropolitan Town Planning Commission released a report recommending an underground city bypass from Richmond to North Melbourne stations via Exhibition and Victoria streets.

[3] The Victorian Railways promoted another route in 1950 as part of the Operation Phoenix rehabilitation plan, the line running from Richmond towards Jolimont station, under the Fitzroy Gardens and Lonsdale Street then turning north to North Melbourne station.

It stated bluntly that the aim of the loop was not just to relieve crowding at Flinders Street, but to win back patronage from private cars, and if it did not then the project was a waste of time and resources.

[1] The 'City of Melbourne Underground Railway Construction Act' was passed in 1960, and test bores were sunk by the Mines Department in 1961, but no funding was provided.

[1] The project was financed using debentures, with the State Government paying 60% of the cost and a special city levy from 1963 funding the remainder.

The first completed tunnel was the Burnley Loop, with the final breakthrough made on 8 June 1977 near the Museum station site.

During the excavation of Museum station, La Trobe Street and its tram tracks were temporarily relocated to the south onto the site of what is now the Melbourne Central Shopping Centre from December 1973, and were moved back in 1978.

[6] While the final cost was $500 million, the opening of the loop helped reverse a 30-year trend of falling suburban rail patronage.

[13] In 2021, seven-car High Capacity Metro Trains were introduced to the City Loop on the Caulfield tunnel.

[21] The upgrade was originally started under the Napthine Liberal government in 2014 and was significantly delayed after the collapse of the contractor while works were underway.

[22] The north-south tunnels were first recommended by the Eddington Transport Report in 2008 as a way to increase the central city's rail capacity.

[23] The tunnel involves the construction of five new underground stations at Arden, Parkville, State Library, Town Hall and Anzac.

Once complete, the reconfiguration would help the network to run seven independent lines with dedicated access in the CBD.

[27] According to Infrastructure Victoria, the project would deliver two-thirds of the capacity uplift of the Metro Tunnel for a fraction of the cost.

[27] The main purpose of reconfiguring the City Loop is to allow more services to operate across the network using existing infrastructure.

[27] Infrastructure Victoria envisioned Glen Waverley and Alamein services running through to the Upfield line via the Flinders Street Viaduct and Frankston services running through to the Craigieburn line via the reconfigured City Loop track pair, which differs from the post-reconfiguration network outlined in stage 4 of the 2012 Network Development Plan.

[28] The reconfiguration would also allow for suburban extensions of the rail network, including extending the Upfield line to the northern growth suburbs of Donnybrook, Beveridge and Wallan.

The Burnley and Caulfield tunnels run mostly parallel to each other, beginning at Richmond and ending at Southern Cross.

[32] The eleven remaining metropolitan lines serve the City Loop and are organised into four separate groups: Burnley, Caulfield, Clifton Hill, and Northern.

[32] The Burnley group consists of the Belgrave, Lilydale, Alamein, and Glen Waverley railway lines.

[36] When the Metro Tunnel opens in 2025, Pakenham and Cranbourne services will be pulled out of the loop and instead will operate to Sunbury.

All services on the group operate in a clockwise direction all day, entering the city at Flinders Street and leaving after Parliament.

[38][39] The main reason for the current operational direction is because of the flat junction at Jolimont, which prevents inbound trains from running anti-clockwise without crossing the outbound tracks.

The station received its original name from the Melbourne Museum, which was located within the State Library of Victoria.