There was very low economic growth during this time, along with an unsettle financial system and mild deflation. This was all due to the Great Depression and the First World War.
They traded.
And the Indians shared their land with them.
Secondary sources is the right one
What are you expecting us to answer to This?
...Charged very high prices to move farm products to market
The farmers felt the railroads had monopoly power over them. The farmers essentially had no choice but to send their crops to market on trains. There was not much, if any, competition on most short-line tracks that went through farm areas. Therefore, most farmers had to simply accept whatever price railroads charged to transport crops. Farmers felt the railroads could gouge them by charging high prices and that they, the farmers, had no recourse when this happened. They blamed much of their trouble on this monopoly power.