c. 1915; "1312-The Detroit River Tunnel, has the unique distinction of being the only tunnel of its type ever built. It was constructed in sections, all work being done from the surface of the water without the use of compressed air. The tunnel is operated electrically. Construction was started October 1, 1906, and completed July 1, 1910. The length from portal to portal is 1 3/4 miles, and from summit of grade 2 1/2 miles. It was built by the Detroit River Tunnel Company for the M. C. R. R. at a cost of $8,500,000."; addressed to Mr. R. G. Egli, Marine P.O., Detroit, Mich., Str "St. Clair"; the Canadian entrance is south of Wyandotte Street West between Cameron and Wellington Avenues.