Question: A single example of a PRR MP70 is preserved at a museum that has two what?

Context paragraphs:
Klausen Synagogue: The Klausen Synagogue is nowadays the largest synagogue in the former Prague Jewish ghetto and also a single example of an early Baroque synagogue in the area.  Today the synagogue is administered by the Jewish Museum in Prague.

Pennsylvania Railroad 4935: The Pennsylvania Railroad GG1 #4935 is a preserved electric locomotive.  It is one of 15 remaining PRR GG1 locomotives, and one of two (along with PRR 4800) at the Railroad Museum of Pennsylvania.

Pennsylvania Railroad 3768: PRR 3768 is a Pennsylvania Railroad K4s steam locomotive located in the Railroad Museum of Pennsylvania, outside of Strasburg, Pennsylvania in the United States.  For over a decade, 3768 stood in for the prototype K4s, 3847, and was listed on the National Register of Historic Places in 1979.  It is one of the two remaining K4s locomotives and, along with PRR 1361, was designated the official state steam locomotive in 1987 by the Pennsylvania General Assembly.

PRR MP70: The PRR MP70, also known informally as the "double-deckers", was a class of electric multiple units manufactured by the Pennsylvania Railroad for use on the Long Island Rail Road (LIRR).  The Pennsylvania manufactured three prototypes in the 1930s, and a full fleet of sixty cars in 1947–1949.  They were among the first examples of bilevel rail cars in the United States.  The design was unpopular with both LIRR employees and commuters; the last cars were retired in 1972.  A single example is preserved at the Railroad Museum of Long Island.

Alpine Spaniel: The Alpine Spaniel is an extinct breed of dog which was used in mountain rescues by the Augustinian Canons, who run hospices in the region around the Great St. Bernard Pass.  The spaniel was a large dog notable for its thick curly coat.  One of the most famous specimens of the Alpine Spaniel is Barry, however his preserved body has been modified on more than one occasion to fit with descriptions of the extinct breed from earlier time periods.  Due to the conditions in the Alps, and a series of accidents, extinction was discussed as a possibility by authors during the 1830s, and at some point prior to 1847 the entire breed was reduced to a single example due to disease.  Evidence held at the Natural History Museum in Bern show that two distinct breeds of dog were being used in the area during this time period.  The breed is thought to be the predecessor to the modern St. Bernard and the Clumber Spaniel.

Pennsylvania Railroad 3750: PRR 3750 is a Pennsylvania Railroad K4s steam locomotive located in the Railroad Museum of Pennsylvania, outside of Strasburg, Pennsylvania in the United States.  For over a decade, 3750 stood in for the prototype K4s, 1737, and was listed on the National Register of Historic Places in 1979.  It is one of the two remaining K4s locomotives and, along with PRR 1361, was designated the official state steam locomotive in 1987 by the Pennsylvania General Assembly.

Pennsylvania Railroad class E6: Class E6 on the Pennsylvania Railroad was the final type of 4-4-2 "Atlantic" locomotive built by the railroad, and second only to the Milwaukee Road's streamlined class A in size, speed and power.  Although quickly ceding top-flight trains to the larger K4s Pacifics, the E6 remained a popular locomotive on lesser services and some lasted to the end of steam on the PRR.  One, #460, called the Lindbergh Engine, is preserved at the Railroad Museum of Pennsylvania.

Hughes H-4 Hercules: The Hughes H-4 Hercules (also known as the Spruce Goose; registration NX37602) is a prototype strategic airlift flying boat designed and built by the Hughes Aircraft Company.  Intended as a transatlantic flight transport for use during World War II, it was not completed in time to be used in the war.  The aircraft made only one brief flight on November 2, 1947, and the project never advanced beyond the single example produced.  Built from wood because of wartime restrictions on the use of aluminum and concerns about weight, it was nicknamed by critics the "Spruce Goose", although it was made almost entirely of birch.  The Hercules is the largest flying boat ever built, and it has the largest wingspan of any aircraft that has ever flown.  It remains in good condition and is on display at the Evergreen Aviation & Space Museum in McMinnville, Oregon, United States.

Pennsylvania Railroad class E44: The PRR E44 was an electric, rectifier-equipped locomotive built by General Electric for the Pennsylvania Railroad (PRR) between 1960 and 1963.  The PRR used them for freight service on the Northeast Corridor.  They continued in service under Penn Central and Conrail until Conrail abandoned its electric operations in the early 1980s.  They were then acquired by Amtrak and NJ Transit, where they lived short lives; all were retired by the mid-1980s.  One is preserved at the Railroad Museum of Pennsylvania.

Railroad Museum of Long Island: The Railroad Museum of Long Island is a railway museum based on the North Fork, of Long Island, New York, in the United States.  It has two locations, a main location in Riverhead, and a satellite location in Greenport, west of the North Ferry to Shelter Island.  Both facilities contain active model railroad displays and gift shops.

Supporting paragraphs: PRR MP70 Railroad Museum of Long Island
Answer: locations