The Elkins Act, passed by Congress in 1903, required railroads to charge freight customers only the offiically published rates, and made illegal rate cutting and rebates. The act was favored by the railroads themselves, because they were annoyed at the many demands for rebates.
It supplemented the Interstate Commerce Act of 1887 by providing more specific methods of procedure and penalties for failing to follow the rules. The Elkins law provided for prosecution and punishment of railroad corporations, as well as their agents and officers, who gave or received rebates and made it a misdemeanor to deviate from published rates.
- Ripley, W. Z. Railroads, Rates and Regulation (1912) full text online