Question: On what railway does the train service formerly called the "Adelaide Express" run?

full_context: Document 1: Main Southern railway line, New South Wales: The Main Southern Railway is a major railway in New South Wales, Australia. It runs from Sydney to Albury, near the Victorian border. The line passes through the Southern Highlands, Southern Tablelands, South West Slopes and Riverina regions.
Document 2: National Railway Museum, Port Adelaide: The National Railway Museum, Port Adelaide, South Australia, is Australia's largest railway museum with over 100 exhibits on display, primarily from the Commonwealth and South Australian Railways. First opening its doors in 1970, the Museum moved to its larger and current premises in 1988.
Document 3: The Overland: The Overland is an Australian passenger train service between Melbourne and Adelaide. It first ran in 1887 as the "Adelaide Express", but South Australians have always referred to the train as the "Melbourne Express". It was given its current name in 1926. Now operated by private company Great Southern Rail, the train completes two return trips a week covering 828 kilometres between the state capitals. Originally an overnight train, it now operates during the day.
Document 4: Southern Aurora: The Southern Aurora was an overnight express passenger train that operated between Australia's two largest cities, Sydney and Melbourne. First-class throughout, including the dining facilities, the "Southern Aurora" featured all-sleeper accommodation. The train first ran on 16 April 1962 after the opening of the North East standard gauge line from Melbourne to Albury, eliminating the break-of-gauge between the capital cities.
Document 5: NSW TrainLink: NSW TrainLink is an Australian brand for the medium and long distance passenger rail and coach services of the New South Wales Government's transport authority, Transport for NSW. NSW TrainLink services operate throughout New South Wales and extend into the neighbouring states and territories of Victoria, Queensland and the Australian Capital Territory. Train services are operated by the government's NSW Trains. Coach services are contracted to private operators.
Document 6: Outer Harbor railway line: The Outer Harbor railway line is a suburban branch line in Adelaide, South Australia. It runs from Adelaide station through the north western suburbs to Port Adelaide and Outer Harbor. It is 21.9 kilometres in length, and shares part of its run with the Grange line. It is operated by Adelaide Metro.
Document 7: Willunga railway line: The Willunga railway line ran through the southern Adelaide suburbs from Adelaide railway station to Willunga, over 45 km long (longer than the current Gawler line, 42.2 km ). The line was opened in Willunga by the Governor of South Australia Sir Henry Galway on 20 January 1915, and initially had 16 stopping places between Adelaide and Willunga. It closed beyond Hallett Cove in 1969 and was dismantled in 1972. The Seaford railway line continues from Hallett Cove along a different alignment before rejoining the route of the old line between Seaford Road and Griffiths Drive.
Document 8: Tonsley railway line: The Tonsley railway line is a suburban commuter line in Adelaide, South Australia that stems off the Seaford line at Mitchell Park to end opposite Science Park and close to the Flinders University and the Flinders Medical Centre. The line is single track for most of its length, from Celtic Avenue near Mitchell Park station to the terminus at Tonsley, with two intermediate stations. Services operate every 30 minutes on weekdays with no trains operating at night or on the weekend.
Document 9: Melbourne–Adelaide railway: The Melbourne–Adelaide railway is a standard gauge railway corridor that runs between the cities of Melbourne, Victoria and Adelaide, South Australia. Most of the current traffic is freight, though the only named and perhaps best known regular train is the twice-weekly passenger service "The Overland", operated by Great Southern Railways
Document 10: South Australian Railways East-West Stock: This article outlines the history of the 24 Corten steel vehicles with corrugated sides, constructed by the South Australian Railways and primarily used on the East-West Express from Adelaide to Port Pirie. The South Australian Railways broad gauge system had been extended north in 1937 to meet a southern extension from Port Augusta on the Commonwealth Railways' standard gauge system, creating Port Pirie as a break-of-gauge and transshipment point. To encourage passengers to use the line despite the inconvenience of changing trains, in 1947 the Cafeteria Car was constructed and used on the services to and from Adelaide, in conjunction with the mid-1930s Steel carriage fleet. In 1964 the first airconditioned sitting cars entered regular service on the East-West Express, and construction of those continued through to 1967 with a total of nine sitting cars and fourteen vans.
Document 11: Emerson Crossing: Emerson Crossing, the 'South Road Overpass' or simply 'the Overpass' are the informal names given to the intersection of South Road, Cross Road and the Seaford railway line in Adelaide, South Australia. South Road crosses north-south over both Cross Road and the diagonal railway via a large bridge built in the early 1980s. This was done in an attempt to cater for the ever increasing amount of traffic which went through the intersection and was constantly congested during peak hour times. Emerson Railway Station is located in the north eastern corner of the crossing. The train station and crossing are both named after Emerson Street, a small dead end road just north of the intersection along South Road, in the suburb of Black Forest.
Document 12: Western Highway (Victoria): The Western Highway is the Victorian part of the principal route linking the Australian cities of Melbourne and Adelaide with a length of approximately 314 km of single carriageway then 156 km of dual carriageway known as the Western Freeway. It is a part of the National Highway network and designated as National Highway A8 and M8. The western end continues in South Australia as the Dukes Highway, the next section of the Melbourne–Adelaide National Highway. The Western Freeway joins Melbourne's freeway network via the Western Ring Road, in the middle western suburbs of Melbourne.
Document 13: Adelaide–Darwin railway: The Adelaide–Darwin railway is a south-north transcontinental railway in Australia, between the cities of Adelaide, South Australia and Darwin, Northern Territory. Between 2000-2004 the line was extended from Alice Springs to Darwin as a Build, Own, Operate and Transfer back (BOOT) project by the AustralAsia Rail Corporation. This replaced the former narrow gauge line from Darwin to Larrimah and the narrow gauge/standard gauge Central Australia Railway from Port Augusta to Alice Springs which used a different route up to 200 km to the east.
Document 14: Sydney–Melbourne rail corridor: The Sydney–Melbourne rail corridor is an approximately 960 km standard gauge railway corridor that runs between Melbourne and Sydney, the two largest cities in Australia. Freight and passenger services operate along the route, such as the NSW TrainLink XPT passenger service. The XPT offers a day and night service in each direction.
Document 15: Adelaide Steamship Company: The Adelaide Steamship Company was formed by a group of South Australian businessmen in 1875. Their aim was to control the transport of goods between Adelaide and Melbourne and profit from the need for an efficient and comfortable passenger service. For the first 100 years of its life, the main activities of the company were conventional shipping operations on the Australian coast, primary products, consumer cargoes and extensive passenger services.
ground_truth: Melbourne–Adelaide railway