In 1935, Gaumont-
Along the way, Mack and Robbie have to deal with jittery investors, scheming financiers, mysterious diseases brought on by subterranean gas, and the odd volcano. Since this isn't sufficiently melodramatic, Mack also finds that his insane work schedule estranges him from his wife Ruth (Madge Evans), who tops it all off by going blind.
The plot may be a bit on the potboiler side, but the engineering is fairly sound, if insanely overblown. The most fantastic bit isn't the radium drill, but the finances of building the tunnel. How a handful of investors, even if they are all as rich as Bill Gates, could afford to back a 3,000 mile long, vacuum sealed, electromagnetic rail tunnel stretches the imagination more than contemplating an edible Hot Pocket.