Burlington route on October 23, 1936, one of the new Denver Zephyrs set a new world's speed record for a long - distance non-stop run by dashing from Chicago to Denver in 12 hours, 12 minutes . . . 1017 miles at an average speed of 83.3 m.p.h. Top Speed on this spectacular run exceeded 116 miles an hour. It slashed by 53 minutes the previous record run of the original Zephyr, from Denver to Chicago in May, 1934.