The Chicago, Burlington & Quincy Railroad (CB&Q) bridge crossing of the Ohio River at Metropolis, IL holds many numerous outstanding facts not the least of which is that the first Train rumbled across it's mile long length on December 15, 1917.
This penny postcard portrays an artists rendering of CB&Q RR bridge
The Metropolis Bridge Design
A critical design factor of the CB&Q Bridge at Metropolis was The US War Department's requirement for a channel width of 700 feet. Expecting traffic to grow over the years, Burlington wanted a double track bridge that could support Cooper E-90 live loading. This showed a tremendous amount of foresight for the day (Cooper E-90 design loading is currently specified by several railroads for permanent structures that may be expected to be in service for 100+ years).
A complicating factor at the Metropolis site was that bedrock was approximately 230 feet below low water level. This depth prohibited founding the piers on the bedrock, instead the piers are founded on a thick quartz sand layer at approximately 75 feet below low water level. Founding the piers on a substrate that could allow them to settle over time prohibited many bridge designs. CB&Q Chose to build a Simple Truss Bridge designed and built using Silicon Steel instead of the normal High Carbon Steel and specifying an even stronger nickel steel for certain members of the bridge allowing the bridge to be made lighter.
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