New Eight Mile Tunnel Opened Under Rockies

Manawatu Times, Volume LIII, Issue 6667, 21 July 1928, Page 1 (Supplement)

New Eight Mile Tunnel Opened Under Rockies

Three Years* Work for 1,500 Men Completed LOWERS GRADE 500 FEET What is said to be the longest tunnel in the Western Hemisphere has just been opened in the State of Washington. It is eight miles long, and is part of the Great Northern Railway system that connects St. PauJ and Minneapolis, and eastern points, with the Pacific' Coast, The new Cascade Tunnel, as it is called, passes through the Cascade Mountains from the small town of Berne, the eastern terminus, to Scenic, a village noted for its medicinal hot springs. The completed tunnel is 24 feet high and 16 feet wide.

For the last three years, 1,500 men have been at work on. this giant tunnel. ■lt lowers the mountain grade by more than 500 feet. The old road, now to be abandoned, followed a track curvature of seven complete ■ circles. The new road follows a straight line through the, mountains, thereby reducing the mileage between eastern cities and Pacific Coast towns. The new tunnel eliminates more than six miles of snowsheds. The maintenance of snowsheds through mountain passes is a heavy expense item on railroad treasuries. But the sheds must be there to protect trains from avalanches of rock, snow, and timber. It is calculated that the annual cost of maintaining snowsheds will be greater than the interest charges.

A temporary tunnel was sunk alongside the new one as a line of communication for the hundreds of workmen drilling and blasting along the main line. The temporary tunnel, has been kept well ahead of the work on the main tunnel. By means of side drifts cut over to the route of the main tunnel as often as practicable, it is explained, many working faces were created. Ordinarily there are but two working faces iii a tunnel —one at each end. Inasmuch as only a limited number of men can work on one face, these extra faces, together with the additional

transportation facilities afforded -by the pioneer (temporary) tunnel, have enabled the contractors to shatter all world records for. speed in this kind of. tunneling. The pioneer tunnel also serves as a drainage channel, carrying off the water which seeps in, and sometimes pours in from the newlyopened seams in the granite. How Work Was Speeded To construct, the Cascade Tunnel with the speed, desired, it was necessary to station large forces of men through the centre of the Cascade Range. This was accomplished by means of the pioneer temporary tunnel; 'To facilitate work, a shaft was sunk from the surface of the ground into the main, tunnel. In this way, the contractors were able to send their huge shovels, mucking machines, and rock trains into the heart of the mountains without waiting for crews driving in the main tunnel from the east. While, the now main tunnel will not ;be entirely tracked and electrified until the end of the present year, it opened, for the first party of inspectors on May T. A member of this party describes' the trip made on a •temporary trolley-car. A Journey Through

“There is a dull . roar. As we advance it becomes deafening. It sounds like a concentrated boiler shop., A dust that is nothing more than condensed moisture fills the air, the electric lights converting it into a • reddish yellow haze. We follow down the tracks to the drill carriage. Four mounted drills are battering their way into ’ the solid granite. Eight or ten men are working on this machine. The ' scene suggests four machine-gun nests operating under an enemy barrage. .“The -drill holes are driven from 10 to 14 feet into the rock, each machine accounting for from 20 to 30 holes. When the facing; is sufficiently penetrated to assure a satisfactory shattering of the rock—usually a three or four hours’ task—rthe .drill carriage moves back, the powder crew loads the holes, electricians, instal a maze lows; advances the tunnel another 10 of : wiripg, .and 'the blast which folto J 5 feet. ; " '■ “The ’ drill crows are the ‘shock troops’ in this ’ advance under the Cascades. For two and a-half years these machines,;, distributed in different places under the Cascades, have been battering at these granite walls day'and’night, Sundays and holidays, without cessation; Shifts are changed at:,the handles of the drills.

.-Enlargement' . operations follow closely bn the • heels of the centreheading' crews. • More drill crews, powder gangs; track layers, and shovel outfits . bring;the, Tunnel to its full size,” ■