The train was a social change in the 1800's. The train gave a faster and safer passage west. More started started going west. Instead of of having to use a hand cart the passage was easier. More middle class and upper class started to go west. With this many states (at the time territories) grew. With more came more removal of land.
"The development of railroads was one of the most important phenomena of the Industrial Revolution. With their formation, construction and operation, they brought profound social, economic and political change to a country only 50 years old." (www.ushistory.orb/us/25b.asp)
"Trains introduced new innovations in the continuing search for the easiest way to move large lads of passengers and goods quickly and efficiently from one place to another. The train linked together several cars or vehicles into one long caravan." (http://www.loc.gov/teachers/classroommaterials/connections/railroad-maps/history.html)
"As we know, this great nation would not have grown and prospered as it did without the railroads." (http://www.american-rails.com/railroad-history.html)
As you see trains where the most significant change in the 1800s.