Entrance to Detroit River tunnel

View of entrance to Detroit River tunnel with railroad cars on tracks near tunnel entrance. Truss bridge crosses over railroad tracks; commercial buildings in background. Printed on front: "Approach and entrance to Detroit River tunnel, Detroit, Mich." Printed on back: "The Detroit River tunnel has the unique distinction of being the only tunnel of this 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 3/8 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. Published by Wolverine News Co., Detroit, Mich. Made in U.S.A. C.T. Co., Chicago, A-17411."