The Union Pacific Railroad's M-10003, M-10004, M-10005, and M-10006 were four identical streamlined 2-car power car diesel-electric train sets delivered in May, June, and July 1936 from Pullman-Standard, with prime movers from the Winton Engine Corporation of General Motors and General Electric generators, control equipment and traction motors. One was for the City of San Francisco, two were for the City of Denver, and one was a spare set intended for both routes. In 1939, M-10004 was split and converted into additional boosters for the other sets, now renumbered CD-05, CD-06, and CD-07, all running on the City of Denver. The M-10001 power car became the other third booster. In this form, the three power sets ran until they were replaced by E8 locomotives in 1953, at which point they were scrapped.

A streamliner is a vehicle incorporating streamlining in a shape providing reduced air resistance. The term is applied to high-speed railway trainsets of the 1930s to 1950s, and to their successor "bullet trains". Less commonly, the term is applied to fully faired upright and recumbent bicycles. As part of the Streamline Moderne trend, the term was applied to passenger cars, trucks, and other types of light-, medium-, or heavy-duty vehicles, but now vehicle streamlining is so prevalent that it is not an outstanding characteristic. In land speed racing, it is a term applied to the long, slender, custom built, high-speed vehicles with enclosed wheels.