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Union Pacific



February 12, 1934

M-10000 Streamliner Debuts

M-10000 was the first of 11 streamlined “M” units delivered to Union Pacific in the 1930s and 1940s. The “M” stood for “motor,” and designated locomotives that were powered by internal combustion. This first streamliner, made of aluminum alloy, was a three-car day train; sleeping cars were added in subsequent models. Fully loaded with 116 passengers, crew and baggage, M-10000 weighed far less than a conventional steam train and used less horsepower. It was nicknamed “Lil’ Zip” and was recognizable by its modern shape and vibrant Armour Yellow paint job.

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By 1936, Union Pacific’s shiny new Streamliners had begun to attract passengers back to the railroad, but the Depression was keeping passenger counts low. UP Chairman Averell Harriman decided that Americans needed a destination that was new and completely different to convince them that vacationing was possible again. In December 1936, the company opened Sun Valley Resort near Ketchum, Idaho. The event also marked the debut of the world’s first two chair lifts, created by UP engineer Jim Curran in the Omaha Shops.

Union Pacific celebrates the shared stories that have shaped our country since 1862. We invite you to explore how the nation’s largest railroad came to be and how UP continues to build America with innovation and tenacity, touching the lives of nearly every citizen.