Economic Effect-Railroads added significant economic growth to the network and contributed advantages all on its own.
https://economics.uchicago.edu/workshops/Hornbeck%20Richard%20-%20Railroads.pdf
Linking the Nation-Early railroads may seem to have linked different regions when many only extended to less than fifty miles.
http://www.ushistory.org/us/36a.asp
Linking across Continent- The dream of a transcontinental railroad, linking the Atlantic and Pacific oceans, stretched back many years but had always been lost due to sectional quarrels over the route.
http://en.wikipedia.org/wiki/Transcontinental_railroad
Social Effect-The railroad ended the relative isolation and tied people together.
http://answers.yahoo.com/question/index?qid=20090713154554AAOJzta