Answer:
To regulate railroad shipping rates
Step-by-step explanation:
The grange was an organization that was formed to improve farmer's standard of living, During that time, many farmers felt that the fees that they need to pay to distribute their product was too high. Leaving them with very little profit from selling their crops.
This is why one of the Grange's political goal is to regulate railroad shipping rates. At that time, train was the most effective method of transportation for these farmers. (trucks haven't been invented). They believe that using government influence to create a price ceiling for railroad shipping will help the farmers increase their revenue.