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 Railroad 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, the prototype, is preserved at the Railroad Museum of Long Island.