Introduction, bodies and machines -- The tempo of life is out of control, and then righted -- The jazz train and American musical modernity -- African American modernism and the techno-dialogic : from John Henry to Duke Ellington -- Swinging the machines : big bands and streamliner trains -- The standardized white girl in the pleasure machine : the Ziegfeld Follies and Busby Berkeley's 1930s musicals -- Tap dancers rap back at the machine -- America's national folk dance : the Lindy hop -- The world of tomorrow...in the groove : swinging the New York World's Fair, 1939-40 -- Conclusion: the continuing importance of swinging the machine.