The railroad monopolies had control over the entire railroad business which made them rich and powerful, when railroads came, many people saw the chance to make money, settlements did not need to be self sufficient anymore. They could order things to come in by train on the railroads. The railroad owners were worried the industries supporting them, such as the iron industry, might crash, so they became monopolies controlling large amounts of businesses all together in a big conglomerated mess. The US made the Anti Trust act to fix that problem and make things fairer for the consumers.
