Bridges: Railroad Bridges
Bridges had to precede the growth of railroads. Railroads covered long distances and permitted trade among buyers and sellers located hundreds of miles apart, but transporting freight over great distances meant that many rivers had to be crossed. The most costly components of a railroad, and the most time-consuming to complete, were the bridges. Railroad bridges had to be of superior construction to support the weight of steel tracks and fully loaded trains. In many cases, because of the cost of building the bridges, some railroads had to initially use ferryboats to get trains across wide rivers until the bridges could be built. For example, the Illinois Central Railroad used large steamboats to ferry entire trains across the Ohio River for several years until the bridge was completed at Cairo, Illinois, in 1869. The importance of railroad bridges is demonstrated by the fact that the railroad bridges in the Confederate states were among the favorite targets of Northern troops during the U.S. Civil War.
Bridges provided the link that allowed for countrywide transportation services—whether roads or railways. Although railroads still own their own bridges, the era of privately owned toll bridges connecting roads ended during the early twentieth century, when these bridges were taken over by state highway departments. In some cases, the tolls continued but were assessed by a quasi-governmental bridge authority.
Bridges are still as valuable as ever, andtheir importance has made them a public good, built and maintained by state funds. The collapse of a bridge on Interstate 35W over the Mississippi River in Minneapolis in August, 2007, raised questions about the conditions of the country’s aging bridges. The Federal Highway Administration subsequently issued a report stating that, as of 2007, more than 150,000 of the nearly 600,000 bridges in the United States were in need of repairs or upgrading, estimated to cost $140 billion.