On January 12, 1929, Great Northern Railway opened the nearly 8-mile Cascade tunnel, the longest tunnel in the Western hemisphere at that time, after 3 years of construction, for public travel in the state of Washington. NBC radio, with 36 participating stations, carried a dedication program on the air to commemorate the event live, with host Philips Carlin at the studio in New York and emcee Graham McNamee on location at the tunnel. Guests on the program included Great Northern president Ralph Budd, President-elect Herbet Hoover, and musical guests George Olsen and His Music and contralto Ernestine Schumann-Heink. The musical guests were there to entertain radio listeners during the about 40-mintue inaugural 8-mile journey of the Oriental Limited train thru the tunnel, with Graham McNamee describing his ride when completed. The program finished with a promo for NBC's new drama radio series, "Empire Builders", featuring the Oriental Limited train as it's setting for storytelling, and named for Great Northern's founder, James J. Hill.
Disclaimer: The original live dedication program ran into overtime at 67 minutes. For the purpose of this trimmed video, I have edited the contents down to a more accessible 14+ minutes, with guest speeches shortened. Also, the guest musical selections used to fill time on the original broadcast had to be removed due to TH-cam copyright issues.