Unknown World (1951)
With the cyclotram, an atomic-powered rock-boring vehicle, Dr. Jerimiah Morley leads an expedition into a subterranean world.
Directed by: Terry O. Morse
Starring: Bruce Kellogg, Otto Waldis, Jim Bannon, Tom Handley, Dick Cogan, George Baxter
Links: IMDb, Movie posters, Movie stills