After falling into a state of disrepair and neglect, in the 2000s the line underwent major civil engineering upgrades and, progressively, 5.5 kilometres (3.4 miles) of route extensions; and received a new tram fleet.

A succession of services followed until in 1907 the South Australian Government established the Municipal Tramways Trust (MTT), which bought out their private-sector owners.

By the 1950s, the network was losing money and being replaced by a fleet of petrol-driven buses and trolleybuses powered by double overhead electric wires.

In early 1855, less than twenty years after the colony was founded, South Australia's first horse tram began operating between Goolwa and Port Elliot on the Fleurieu Peninsula.

[3] Just over twenty years later Adelaide became the first city in Australia to introduce horse trams, and eventually the last to discard them for more modern public transport.

Private commercial interests lobbied government for legislative support, over Adelaide council's objections related to licensing and control.

As a result, the Government of South Australia passed an 1876 private act, authorising construction of Adelaide's first horse tram network.

[7] Completed in May 1878,[8] services began in June from Adelaide to Kensington Park with trams imported from John Stephenson Co of New York, United States.

[9] Until 1907, all horse tram operations were by private companies, with the government passing legislation authorising line construction.

[4] Most of the companies operated double-decker tram, although some were single level cabs with many built by John Stephenson Co, Duncan & Fraser of Adelaide, and from 1897 by the A&ST at Kensington.

The trial was unsuccessful due to the batteries poor capacity, and the promoters' deaths in a level crossing accident shortly after precluded further experiments.

With a population of 162,000 the slow speed of the trams, and the lines subsequent low traffic capacity, made them inadequate for public transport needs.

[32] To cope with variable loads on the system, very large storage lead–acid batteries were installed, the initial one at East Terrace comprising 293 cells and a 50 ton tank of sulphuric acid.

The line was closed to be rebuilt to 4 ft 8+1⁄2 in (1,435 mm) standard gauge, electrified at 600 Volts DC and converted to tramway operation, reopening in late 1929.

The Port Adelaide line, which until that time had still used horse trams, began to be converted to electric operation in 1914 and opened on 3 April 1917.

[35] On 18 September 1918, a tram line opened from Sturt Street, via West Terrace and then Anzac Highway (then Bay Road[36]) to Keswick.

After redevelopment of Anzac Highway in the 1930s, the tram line was eventually truncated at the new Keswick Road Bridge in March 1939, at a stop known as Wayville West.

A decision was made to trial trolleybuses, and a converted petrol bus began running experimentally on the Payneham and Paradise lines in 1932.

By notionally marking each ticket as a fare from the pickup point to Murrayville, Victoria (but allowing passengers to board or alight sooner) companies avoided having to abide by the regulation for some time.

[52] In 1951–1952 the MTT lost £313,320 and made the decision to convert the Erindale, Burnside and Linden Park lines to electric trolleybuses.

[53] Late the same year, with driver safety concerns about the conflict with increasing traffic on the road, the Glen Osmond line was temporarily converted to motor buses.

The Tramway Museum, St Kilda, a half-hour's drive north of the city centre, has at least one example of each 20th century tram.

[44] A 1.2-kilometre (0.75 mi) extension of the line from the Victoria Square terminus was announced in April 2005, which would see trams continue along King William Street and west along North Terrace through Adelaide railway station and the western city campus of the University of South Australia.

[57] Further extensions at that time were the subject of public debate; Tourism Minister Jane Lomax-Smith expressed support for the line to be extended to North Adelaide and Prospect although the Transport Minister stated that this was not a practical option,[58] with his preferred option the creation of a fare free city loop.

The first extension, completed in early 2010, was from the existing North Terrace terminus to the Adelaide Entertainment Centre in the inner north-west suburb of Hindmarsh, with a park and ride service set up on Port Road.

[60] Following the expected electrification of the Outer Harbor and Grange railway lines, new tram-trains were proposed to run to West Lakes, Port Adelaide and Semaphore by 2018.

The project was expected to cost $80 million with the contract awarded to a joint venture of Downer Rail and York Civil.

[82][83] Both arrived in the first half of 2007, 111 being diverted to Yarra Trams' Preston Workshops and completing over 400 kilometres of trial running on the Melbourne network.

[90] The trams were delivered in two separate batches of three being landed in Melbourne in September and November 2009 for modifications at Preston Workshops before being moved by road to Adelaide.

[101] To make room for new Alstom Citadis trams at the Glengowrie depot, in December 2017 both were moved to the Department of Planning, Transport & Infrastructure's Walkley Heights facility.