Question: In what year did the museum that preserved South Australian Railways 409 steam locomotive first open its doors?

Context paragraphs:
Locomotive U-127: Russian steam locomotive U-127 is a 4-6-0 locomotive of type Russian locomotive class U, preserved at the Museum of the Moscow Railway next to Paveletsky Rail Terminal in Moscow.  The locomotive was the first Russian steam locomotive preserved.

Victorian Railways H class: The Victorian Railways H class was an express passenger steam locomotive operated by the Victorian Railways from 1941 to 1958.  Intended to eliminate the use of double heading A2 class locomotives on "The Overland" services on the steeply graded Western line to Adelaide, wartime restrictions led to only one locomotive being built.  Nicknamed "Heavy Harry", H220 was the largest locomotive ever built in Australia and the largest non-articulated steam locomotive to run on Australian railways.

Pennsylvania Railroad 5550: Pennsylvania Railroad 5550 is a mainline duplex drive steam locomotive currently under construction in the United States of America.  Upon completion, the locomotive will be the 53rd addition to the Pennsylvania Railroad's T1 steam locomotive class with an approximated year of completion date set for sometime around 2030.  The total estimated cost of PRR 5550 was US $10,000,000, but with the acquisition of an existing long haul tender from the Western New York Railway Historical Society in August 2017, the total cost is now estimated to be closer to US $7,000,000.  The project is following some of the same protocols and objectives faced during the prior construction of the LNER Peppercorn Class A1 steam locomotive "Tornado" in the United Kingdom to help ensure its success.  The T1 Trust has also worked closely with many United Kingdom based steam locomotive foundations to aid in the construction of PRR 5550.  Construction of the locomotive began in 2014 with the casting of the proposed locomotive's keystone shaped number plate with several other key pieces such as two of the large Boxpok driving wheels either complete or under construction as of August 2017.

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.

Southern Cross Express: The Southern Cross Express was a luxury train operator in Australia.  It was launched in June 1985 as Steam Age operating out of Melbourne on the Victorian Railways broad gauge network.  Services were operated by steam locomotive R766 and six South Australian Railways carriages.

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.

Santa Fe 3751: Atchison, Topeka & Santa Fe 3751 is a 4-8-4 "Northern" type steam locomotive built in 1927 by the Baldwin Locomotive Works for the Atchison, Topeka and Santa Fe Railway.  Built as the first Northern type steam locomotive for the Santa Fe, the 3751 served in passenger duties until being retired in 1953.  The locomotive was then placed on display in San Bernardino, California until it was restored to operating condition in 1986.  The 3751 is currently located in the Central City East neighborhood of Los Angeles and is listed on the National Register of Historic Places.  Today, Santa Fe 3751 holds the distinction of being the oldest surviving 4-8-4 type steam locomotive in the world.  The locomotive is currently owned and operated by the San Bernardino Railroad Historical Society who use the locomotive to haul occasional mainline excursion trains.  It is currently due for its 15-year inspection, so it will be out of service for about 3-4 years.

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.

BR Standard Class 9F 92220 Evening Star: BR standard class 9F number 92220 "Evening Star" is a preserved British steam locomotive completed in 1960.  It was the last steam locomotive to be built by British Railways.  It was the only British main line steam locomotive earmarked for preservation from the date of construction.  It was the 999th locomotive of the whole British Railways Standard range.

LNER Peppercorn Class A1 60163 Tornado: 60163 "Tornado" is a main line coal-fired steam locomotive built in Darlington, England.  Completed in 2008, "Tornado" was the first such locomotive built in the United Kingdom since "Evening Star", the last steam locomotive built by British Railways in 1960.  It is the only example of an LNER Peppercorn Class A1 locomotive in existence, the entirety of the original production batch having been scrapped without preservation.  The locomotive's namesake is the Panavia Tornado, a combat aircraft flown by the Royal Air Force.  As of April 2017, Tornado became the first steam locomotive to officially reach 100mph in over 50 years on British tracks.

Supporting paragraphs: South Australian Railways 400 class National Railway Museum, Port Adelaide
Answer: 1970