The bridge lately built across the Mississippi at St. Louis has a compound system of steel tubular arches supporting the truss and road-beds. It has three spans of 497, 515 and 497 feet respectively. The middle arch has but one fellow in the world, that of Kuilinburg, in Holland, Its engineer is Captain Eads, and it has lately been opened amidst great rejoicing. It has a double-track railway upon the lower level, and a roadway thirty-four feet wide and two footways each eight feet wide upon the upper level. The Illinois roads which converge upon this viaduct have freight depots near the water, but the passenger trains page through a tunnel 4800 feet in length, beneath the river-side part of the city, and reach the up-town depot. Each span consists of four arches, having two members each, an upper and a lower one. Each member is of two parallel cast-steel tubes nine inches in exterior diameter set closely together, and each made in four segments, whose junctions form ribs. The upper and lower members are eight feet apart. The whole structure is stiffened by systems of diagonal, vertical and horizontal braces.
Taken from "THE FIRST CENTURY OF THE REPUBLIC" HARPER'S
NEW MONTHLY MAGAZINE, VOL. L DEC 1874-MAY 1875. page 228.
©1998, 1999, 2000 by Carol Dean