Answer:
Interstate Commerce Commission
Step-by-step explanation:
The Hepburn Act of 1906. managed to strengthen the power of the Interstate Commerce Commission, giving them the power to control the prices of railroads and setting them to maximum rates.
The companies were affected by this, as they had to accept the conditions ICC would make unless they wanted to challenge it in the court.
ICC could also have a look into the records, which was impossible beforehand, which made the bookkeeping system easier and more accessible.