What was the impact of railroads on the US in the late 19th century?
The geography of the American continent lent itself to the transport of raw materials from unpopulated to populated (and thus industrialized) areas - usually west to east. In Europe, by contrast, railroads mainly brought small-town populations into the cities. A seminal and entertaining novelization of this process can be found in The Octopus. The laying of track in the Great Plains was relatively easy; it was the Rockies (and the Sierra Nevadas that proved most difficult but, ultimately, the most financially rewarding.