Robert Lowery

Steve Langtry

Lyle Talbot

Rudolph Toller

Arthur Hohl

Clayton

Oscar O'Shea

Capt. Ethan Perrin

Joe Devlin

Louis Schaber

Francis McDonald

Batiste

Eddy Waller

Charles Langtry

Marion Martin

Celeste Eltree [Chs. 1-4, 7]

Eddie Quillan

Jug Jenks [Chs. 1-4, 7]

Alec Craig

Chief Engineer [Chs. 1-4, 7]

Ian Wolfe

Hermann Einreich [Chs. 1-2]

Dick Curtis

Craig Cassard [Ch. 1]

Byron Foulger

Dr. Hartman [Ch. 1]

Earle Hodgins

Jean Duval [Ch. 5]

Cy Kendall

Police Chief F. E. Dumont [Chs. 6-8, 11]

Ralph Sanford

Sawyer, the garage owner [Chs. 5, 10]