File:B&LE bridge 1890s.jpg - Wikimedia Commons

Description

English: THE ALLEGHENY RIVER BRIDGE AND VIADUCT. PITTSBURGH, BESSEMER AND LAKE ERIE RAILROAD. Total length combined is 3,538 feet. It consists of a steel viaduct on the North end which is 1,500 feet long, the main girders of which are 65 feet long each, and the tower girders 35 feet long each, with a span over the West Penn Railroad 136 feet long. From the rail to the ground, on the highest point is 125 feet in this viaduct. The river crossing consists of three deck spans, 350 feet long each and 60 feet deep, and one deck channel span 520 feet long, 75 feet deep. The height of rail from low water, at the highest point is about 160 feet. On the south end adjoining the river span is a span over the Allegheny Valley Railroad 207 feet long and 30 feet deep. The height from the rail of the Allegheny Valley Railroad to the rail of the P. B. & L. E. R. R. is 111 feet. The piers under the 350 feet spans are 102 feet high above low water, and under the 520 foot span are 88 feet high above low water. These piers set on a timber grillage below the bottom of the river, which in turn sets on piles driven into the gravel bottom as deep as possible, and concrete was put in around the heads of the piles up to the bottom of the grillage. The piers themselves are built of first class masonry shell, filled solidly with concrete.