Question: In what year did the museum, where two South Australian Railways 400 class locomotives are preserved, move to its current location?

full_context: Document 1: Royal National Park railway station: Royal National Park railway station is located in Audley, New South Wales, that serviced travellers to the Royal National Park. It is the terminus of the Royal National Park railway line, now operated by the Sydney Tramway Museum, although the station platform itself is not usable by the heritage trams operating the service. It opened in 1886 as a commuter rail station, forming part of the Sydney railway network. Along with the Royal National Park railway line, it closed in 1991 due to low patronage. The line and station were acquired by the Sydney Tramway Museum and reopened in May 1993.
Document 2: Hejaz Railway Museum: The Hejaz Railway Museum (Arabic: متحف سكة الحجاز) in Medina is a railway museum that was opened in 2006. It is on the grounds of the restored historic Ottoman railway station at Medina, locally called "Istasyun", including a stretch of the historic track and a train shed with originally four tracks. There are several engines and pieces of rolling stock on display, some of which has been transported to the museum from other places along the historic Hejaz railway line. At least one engine has been restored enough to be driveable on the museum tracks. It is, along with the old train station at Mada'in Saleh, one of two museums in Saudi Arabia dedicated to the Hejaz railway.
Document 3: 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 4: 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 5: South Australian Railways 620 class: The South Australian Railways 620 class was a class of 4-6-2 steam locomotives operated by the South Australian Railways.
Document 6: South Australian Railways Z class: The South Australian Railways Z class was a class of 4-4-0 steam locomotives operated by the South Australian Railways.
Document 7: South Australian Railways R class: The South Australian Railways R class, later upgraded to Rx Class was a class of 4-6-0 steam locomotives operated by the South Australian Railways.
Document 8: South Australian Railways 520 class: The South Australian Railways 520 class was a class of 4-8-4 steam locomotives operated by the South Australian Railways.
Document 9: South Australian Railways V class: The South Australian Railways V class was a class of 0-4-4 steam locomotives operated by the South Australian Railways.
Document 10: National Railway Museum Shildon: National Railway Museum Shildon, also known as Locomotion: the National Railway Museum at Shildon or Shildon Locomotion Museum is a railway museum in Shildon, County Durham, England. The museum is a branch of the National Railway Museum (NRM), which is part of the Science Museum Group. Shildon acts as an annex, with important exhibits on display in the NRM's headquarters at York, though major exhibits are regularly rotated.
Document 11: South Australian Railways 500 class (steam): The South Australian Railways 500 class was a class of 4-8-2 steam locomotives operated by the South Australian Railways. They were rebuilt as 4-8-4s.
Document 12: National Motor Museum, Birdwood: The National Motor Museum, Australia, is an automobile museum in the Adelaide Hills in the township of Birdwood, South Australia. Established in 1964 and opened to the public soon afterwards, it is Australia's largest motor museum, with close to 400 vehicles on display.
Document 13: South Australian Railways W class: The South Australian Railways W/Wx class was a class of 2-6-0 steam locomotives operated by the South Australian Railways and later the Commonwealth Railways.
Document 14: 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 15: South Australian Railways 400 class: The South Australian Railways 400 class was a class of 4-8-2+2-8-4 steam locomotives built in the early 1950s. The 400 class locomotives mainly hauled mineral trains on the South Australian Railways' narrow gauge Broken Hill line from 1953 to 1963, when they were replaced by diesel locomotives. They operated as far as far south as Port Pirie and Terowie and as far north as Quorn. The 400 class was temporarily returned to service in 1969 while the diesel locomotives were converted to . Two have been preserved, 402 at the Zig Zag Railway, Lithgow and 409 at the National Railway Museum, Port Adelaide.
ground_truth: 1988