Answer:
Increased factory production resulted in a growing need to transport more goods.
Step-by-step explanation:
Once the Railroads were developed and completed around America, transport of goods were easier and faster than before, factories that needed goods to produce products would receive them in less time than before. Goods would be transported to all corners of the country in a fast velocity. All of this created a commerce boom, people would more things, more things would be produced and more money would be earned. This caused a great economy boost.