Photoelectric system controls traffic in continental divide tunnel

A photoelectric block-signal system controls the traffic of men and materials which constantly flows in both directions in the 13-mile-long $50,000,000 Continental Divide Tunnel now being drilled between Grand Lake and Estes Park, Colo. Part of the Colorado-Big Thompson project of the United States Bureau of Reclamation, this tunnel will bring water from the western slope of the Continental Divide to the eastern side, where it will be used for irrigation and the production of electric power.