Correction:
The USGS map used to identify the location of the Carnall St. Bridge in Fort Smith, as clearly labeled, was approved in 1890 (not 1880) with the USGS land survey around Fort Smith conducted in 1887 (nor 1878). The St. Louis-San Francisco railroad from Fort Smith to Paris, TX had just been completed (in 1887), as shown on the topo map.
Local political support necessary for the future E' Street Bridge, not present in the 1887 USGS survey (as has been noted previously), may have been motivated by the desire for a better bridge connection to the new railroad service in downtown Fort Smith for nearby Indian Territory's wagon-hauled freight and pedestrian business, for which the E Street Bridge was designed to serve.