Answer:
Rail road companies facilitated settlement of the Great Plains because it provided a means of transportation for settlers to get to the location. The government had also provided land to these companies which they sold at an affordable cost to the new settlers. The area was a large expanse of flat land making it easy for newcomers to establish agriculture.
Answer:
Congress
Article 1 of the Congress is huge (just did a project), detailed explanation of the house and senate.
The primary way in which the government encouraged settlement in the west was through the Homestead Act, which gave people free land--while the railroads allowed them to travel there safely.