The Eads Bridge was the only bridge crossing the Mississippi at Saint Louis for most of the latter half of the 1800s. The Eads went bankrupt in 1875, and came under the control of the TRRA, Terminal Railroad Association. The TRRA used their monopoly to raise freight rates through the roof. The rates were so high that ferry service remained practical into the 1920s.

As the 1800s passed, area shippers wanted to break the TRRA and the Eads Bridge monopoly. They organized, forming a Merchants Exchange company in 1886 to build a second bridge. The Merchants Bridge opened in 1890. At last there was an alternative to the costly and increasingly congested Eads Bridge.

The low freight rates were short lived. The Merchants Exchange went broke during the Panic of 1893. The TRRA took over the debt and property of the Merchants Exchange, including the magnificent bridge. TRRA once again had a monopoly on the Saint Louis area bridge and ferry business.

Over the years, the Merchants Bridge took a pounding from ever heavier trains. One result is that the bridge approach trestles had to be replaced in 2005 with modern structures. In addition, in 1988, the steel inside the bridge had to be rearranged to allow for taller cars to pass through the structure to accommodate double stack container cars.