In the case of Chicago and Northwestern Railway Company v. Gray, 1914, the U.S Supreme Court ruled in favor of the railway company. The dispute arose when Mr. Gray was injured while working for the railroad company and sought compensation under Nebraska's Employers' Liability Act which allowed employees to sue their employers for injuries sustained due to negligence on part of fellow servants or co-workers. However, this state law conflicted with federal legislation - specifically, Federal Employers' Liability Act (FELA) that did not hold employers liable for injuries caused by fellow workers’ negligence. The court held that FELA superseded Nebraska's law as per Supremacy Clause of US Constitution; thus making it impossible for Mr.Gray to claim damages from his employer based on a coworker’s negligence under state law since such provision didn't exist in federal statute. This ruling reinforced supremacy of federal laws over conflicting state laws especially where interstate commerce is involved.

In the dissenting opinion for Chicago and Northwestern Railway Company v. Gray, it was argued that the court majority had erred in its interpretation of the law regarding liability for accidents involving railway employees. The dissenting justices contended that an employer should not be held liable if they were unaware of a potential hazard or risk to their employee's safety, as long as they had taken reasonable precautions to ensure workplace safety. They believed this principle applied even when an accident occurred due to equipment failure or malfunction, which was beyond the control of both parties involved. Furthermore, they disagreed with the majority's view on contributory negligence and maintained that any negligence by an injured party should reduce their compensation proportionately rather than completely absolving employers from responsibility.