Answer:
It is used to create railroads.
Step-by-step explanation:
Before the invention of railroads, the only method of travelling from one state to another is by using Caravans. This was very hard to do because it could took months for traders to reach other states by using horses.
The invention of railroads allowed people to reach states at a much faster time. It connected different areas in United States and made it easier for people to distribute their product to another states.