The train made a "Dawn-to-Dusk" dash from Denver to Chicago on May 26, 1934, in a publicity stunt timed to coincide with the opening day of the Century of Progress fair in Chicago. The railroad spared no expense in planning the operations. All other trains along the "Zephyr"'s route were diverted to sidings and the turnouts were spiked into the proper alignment for the "Zephyr"'s run. Track and maintenance of way workers checked every spike and bolt along the train's route to ensure that there would not be any problems, and temporary speed signs were installed along the route to warn the "Zephyr"'s crew of curves that would be dangerous at high speeds. On the day of the dash, every road grade crossing was manned by a flagman to stop automobile traffic ahead of the train and to ensure that the crossing was clear. Stations along the route were protected by local police officers and members of the American Legion and the Boy Scouts of America.