What legislation made it illegal for railroads to fix prices or give rebates to privileged customers?

The legislation that made it illegal for railroads to fix prices or provide rebates to privileged customers is the Interstate Commerce Act. This act was passed in 1887 in response to widespread public outcry against the monopolistic practices of railway companies. It aimed to regulate the railroad industry and ensure fair rates for all customers, particularly addressing issues of price discrimination and unfair practices that were prevalent at the time. The Interstate Commerce Act established the Interstate Commerce Commission (ICC), which had the authority to investigate and prosecute unfair practices in rail transport and was a significant step toward federal regulation of industries that affected the public interest.

In contrast, the Granger Laws were a series of state laws that aimed to regulate railroads but did not achieve the federal regulatory framework established by the Interstate Commerce Act. The Pure Food and Drug Act was focused on consumer protection in the food and drug industry, and the Hepburn Act expanded the powers of the ICC, but it came later, in 1906, and built on the foundation laid by the Interstate Commerce Act. Thus, the Interstate Commerce Act is the legislation that precisely addresses the issues of price fixing and rebates in the railroad industry.