The railroad had several different positive effects on the west. One of the most important ones was an increase in population. Thanks to the railroad, American citizens could now access territories in the west much easier.
Another positive effect of the railroad on the west was a decrease in shipping costs. Before the railroad, it was very expensive to send goods from western territories to the east. Thanks to the railroad, the price of shipping goods dropped dramatically.
Lastly, the railroad allowed for quicker, more efficient travel. Traveling by railroad during the 19th century was much faster than going by horseback or wagon.
If you came to settle on present-day New York City in about 1650, it's most likely that you're of Dutch descent, since they were the highest rate of immigrant at the time.