The interstate commerce commission was established in 1887 to

... monitor the railroad freight business

The Interstate Commerce Commission was created as one of the provisions of the Interstate Commerce Act of 1887. The Interstate Commerce Act made prices to ship goods via railroads fair for all who had products to ship, so that small farmers no longer had to pay more than bigger companies.

Railroads had been giving favorable treatment and prices to major companies for shipping freight on rail lines.  The Interstate Commerce Act of 1887 aimed to end such practices.  The act contained provisions such as:

... All railroads were required to set fair and reasonable shipping rates.

... Charging different rates for a similar service was declared illegal.

... Railroads could not charge more for short-haul services than a proportional rate of long-haul services on the same route.

... Railroads were forbidden from providing favorable treatment to any person or company or location.

... Railroads were required to display their rates and not charge higher than their posted rates.