On what railway does the train service formerly called the "Adelaide Express" run?
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. Melbourne–Adelaide railway:  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 The Overland:  It first ran in 1887 as the "Adelaide Express", but South Australians have always referred to the train as the "Melbourne Express".
Melbourne–Adelaide railway