What changes were brought about due to the expansion of the railroads?

In the 19th century (before as well as after the Civil War), railroads brought many changes to the United States of America. For one thing, trade and commerce increased, with a complementary expansion of industry, especially in the North. For another, settlement of the 'wild West' was made easier, as was increased growth of areas already settled. For yet another, military operations became more sophisticated and generally more power-packed: during the Civil War, Union and Confederate forces could be quickly reinforced or moved to areas of special need due to the rapid transportation provided by railroads.