To accommodate the massive size and strength of the Mississippi River, the Eads Bridge required a number of engineering feats.

The arches were built suspended from temporary wooden towers, sometimes cited as the first use of the "cantilever principle" for a large bridge.

The Eads Bridge became a famous image of the city of St. Louis, superseded only by the Gateway Arch, completed in 1965.

[6] The former railroad deck now carries the St. Louis MetroLink light rail system, connecting Missouri and Illinois stations.

As of April 2014, it carries about 8,100 vehicles daily, down 3,000 since the Stan Musial Veterans Memorial Bridge opened in February 2014.

[7][page needed] The growth of railroads since the Civil War had depressed river shipping trade, and Chicago was fast gaining as the center of commerce in the West.

The bridge was envisioned to restore St. Louis' eminence as a center of commerce by connecting railroad and vehicle transportation across the river.

[8] In an attempt to secure their future, steamboat interests successfully lobbied to place restrictions on bridge construction, requiring spans and heights previously unheard of.

This was ostensibly to maintain sufficient operating room for steamboats beneath the bridge's base for the then foreseeable future.

The unproclaimed purpose was to require a bridge so grand and lofty that it was impossible to erect according to conventional building techniques.

The steamboat parties planned to prevent any structure from being built, in order to ensure continued dependence on river traffic to sustain commerce in the region.

The triple span, tubular metallic arch construction was supported by two shore abutments and two mid-river piers.

His decision resulted from a curious combination of chance and necessity, due to the insufficient strength of alternative material choices.

Eads implemented a building method that he had observed in Europe, whereby masonry was set atop a metal chamber filled with compressed air.

Workers dove into the caisson to shovel sand into a pump that shot it out into the air so the masonry could be sunk into the riverbed.

[8] President Ulysses S. Grant dedicated the bridge on July 4, 1874, and General William T. Sherman drove the gold spike completing construction.

[8] On June 14, 1874, John Robinson led a "test elephant" on a stroll across the new Eads Bridge to prove that it was safe.

Popular belief held that elephants had instincts that would make them avoid setting foot on unsafe structures.

[15] The opening day celebration on July 4, 1874, featured a parade that stretched for 15 miles (24 km) through the streets of St.

[5] The bridge was closed to automobile traffic between 1991 and 2003, when the city of St. Louis, Missouri, completed a project to restore the highway deck.

[5] In 1998, the Naval Facilities Engineering Service Center investigated the effects of the ramming of the bridge by the towboat Anne Holly on April 4 of that year.

[23] The restorations included replacing 1.2 million pounds of struts, bracing, and other support steel dating to the 1880s; removing all paint and corrosion from the superstructure; re-painting the superstructure with a rust-inhibiting coating; repairing damaged structure; rebuilding concrete supports; restoring the brick archways; and upgrading the MetroLink's rails.

[25][dead link‍] While expected to start in 2009, work did not begin until 2012 due to labor disputes and higher-than-expected cost estimates.

City fathers wanted a wagon bridge to the heart of town to highlight the best features of St. Louis.

The work north of Market was assigned to James Andrews, the stonemason overseeing construction of the bridge piers.

The route crossed the Eads Bridge and traveled through the tunnel to Mill Creek Valley and then returned.

A photograph of the St. Louis Bridge Company's coke-burning engine appears on page 38 of Brown's Baldwin Locomotive Works.