For America, the twenties were boom times. New ideas and inventions cascaded almost daily. Anything was possible. There were challenges. Running trains over the highest route in North America, Rollins Pass, was costly and difficult. The effort had bankrupted several railroads. David Moffat dreamed of building a tunnel under the continental divide in 1902. By the twenties, it was badly needed. Charity Hovus, Cam Braun, Dale Smertz,...