The Pioneer Zephyr (unofficially the "Silver Streak") is a diesel-powered trainset built by the Budd Company in 1934 for the Chicago, Burlington & Quincy Railroad (CB&Q), commonly known as the Burlington Route. The trainset was the second internal combustion-powered streamliner built for mainline service in the United States (after the Union Pacific Railroad's M-10000), the first such train powered by a diesel engine, and the first to enter revenue service.
It is now on display at the Museum, of Science and Industry in Chicago.