The post-civil war period was one of great economic expansion for the United States. Transportation develpoments, notably the building of trans-continental railroads, helped spard this growth mastly by making transportation between the east and west easier.
Although railroads were being built in the U.S. since the 1930's this industry bontributed greatly to economic development after the Civil War. Early American railroads were mostly local and were mostly built in the North. However, in 1962 Congress, without Southern representatives, passed the building of America's first transcontinental railroad. The railroad was to go all the way from the northeast to the west coast.
The passage of this first transcontinental line began a trend in America as numerous tycoons such as James Hill. Hill got rich off the building of a number of similar trans-continental lines. These tycoons became some of the first millionaires in the modern United States by running these trans-continental lines as successful buisnesses.
In addition, the building of transcontinental railroads contributed to the settling of the West. First, they facilitated the journey to the West and thus encouraged people to mobe there. Moreover, in order to be successful the transcontinental lines needed to be able to pick up passangers along the route. Therefore, in addition to helping the building of the lines, the federal gevernment provided the railroads a lot of western land to sell to settlers. Thus, the transcontinental railroad aided the settling of the west by selling federally provided land for cheap prices. By 1890 the frontier was closed, slowing the success of the lines in settling the west. These areas quickly grew economically, thus depiction the sparking of economic growth by the transcontinental railroads.
In addition, perhaps the railroads biggest help to the economy was its providing of east access for Western farmers of eastern markets.