Engineer Johnny Munroe is enlisted to build a railroad tunnel through a mountain to reach mines. His task is complicated, and his ethics are compromised, when he falls in love with his boss's daughter
| Actor | Role |
|---|---|
 John WayneJohnny Munroe | Johnny Munroe |
 Laraine DayMaura Alexander Munroe | Maura Alexander Munroe |
 Cedric HardwickeFrederick Alexander (as Sir Cedric Hardwicke)v | Frederick Alexander (as Sir Cedric Hardwicke)v |
 Judith AndersonMiss Ellen Braithwaite | Miss Ellen Braithwaite |
 Anthony QuinnRicky Vegas | Ricky Vegas |
 James GleasonPop Mathews | Pop Mathews |
 Grant WithersFog | Fog |
 Paul FixJoe | Joe |
 Fernando AlvaradoChico | Chico |
 Harry WoodsHolden | Holden |
| MMichael HarveyCurly | Curly |
 Charles TrowbridgeSeñor Tobar | Señor Tobar |
 Martín GarralagaChavez | Chavez |
 Blanca VischerYoung Woman (uncredited) | Young Woman (uncredited) |
 Max WagnerNot listed | Not listed |
| BBrick SullivanForeman with Holden at Fiesta (uncredited) | Foreman with Holden at Fiesta (uncredited) |
 Jan SterlingDancer at Fiesta (uncredited) | Dancer at Fiesta (uncredited) |
| JJulian RiveroPriest (uncredited) | Priest (uncredited) |