The building of the railroad system played a significant role in changing the United States.  The railroad system was very dense, providing transportation in the eastern part of the U.S.  When the railroad moved across the center and through to the western edge of the country, the significance of railroads became even greater.  The new railroad crossed the entire country uniting the two sides of the states with an easy method of travel.  The railway lines cut through the Indian lands deliberately which divided the native people and moved many of them onto reservations.  The railroad decimated the buffalo population upon which the Indians had depended for so long.  Because the native population was moved, many more white settlers came and came far more quickly than previously.  So, the railroad played a significant role in transforming the country from two or three divided sections into one country connected to the rest by the railroad.