Answer: The Granger Movement against the railroads
Step-by-step explanation:
In the late 19th century, the Railroad companies and their Corporate backers had began to act like cartels due to the very important service they provided and the lack of alternatives.
Because industries like Agriculture and others relied on them to transport goods across the country, they started charging higher prices which made farming less profitable.
The farmers then organised themselves into Granges from the 1860s onwards and these granges were able to influence legislature that brought the railroad companies under control by electing people into power that would lobby for such.