From Ohio History Central
The city of Cincinnati provided financial support for the construction of the Ohio and Mississippi Railroad in 1854. The railroad was built parallel to the Cincinnati and Whitewater Canal. By the 1850s, canals were being replaced by railroads, which were able to transport goods more quickly and at cheaper rates. The people of Cincinnati hoped that the new railroad would encourage economic growth in the region.
The Ohio and Mississippi Railroad was an "Erie gauge" railway, meaning that the track rails were six feet apart. This was much wider than the standard distance. Upon completion of the Ohio and Mississippi Railroad in 1857, Cincinnati residents could now travel from the Chesapeake Bay in the East and East St. Louis, Illinois, along the Mississippi River, in the West, on an Erie gauge line. This railroad dramatically enhanced the city’s economic markets. Eventually, the Ohio and Mississippi Railroad became part of the Baltimore and Ohio (B&O) system.