Which of these events first allowed many more settlers to move west?

The completion of the transcontinental railroad connected the eastern United States to the West by rail, making travel faster and easier for large numbers of settlers. The reservation system, the Indian Appropriations Act, and the defeat at Wounded Knee were part of the displacement and confinement of Indigenous people, but they did not provide the same direct means for settlers to travel west.

AI-written and checked against the verified answer.