A high-speed train becomes the star of the film as it rushes from Chicago to Hoover Dam to transport an iron lung to a needy patient.
| Actor | Role |
|---|---|
 Sally BlaneRuth Dexter | Ruth Dexter |
 Charles StarrettTom Caldwell | Tom Caldwell |
 Hardie AlbrightAllan Dexter | Allan Dexter |
 William FarnumB.J. Dexter | B.J. Dexter |
 Irving PichelBronte | Bronte |
 Arthur LakeCrawford | Crawford |
 Theodore von EltzTyler | Tyler |
 Guinn 'Big Boy' WilliamsHiggins | Higgins |
 Edgar KennedyO'Brien | O'Brien |
 Doris DawsonMolly | Molly |
 Ray TurnerSam | Sam |
 Murray KinnellDr. Flynn | Dr. Flynn |