In the case of Union Pacific Railroad Co. v. Sheehan in 1978, the U.S Supreme Court ruled on an issue related to workers' compensation for railway employees under the Federal Employers Liability Act (FELA). The plaintiff, Sheehan, was a railroad worker who had suffered injuries while working and sought damages from his employer, Union Pacific Railroad Company. The company argued that it should not be held liable because Sheehan's negligence contributed to his injury. However, the court rejected this argument based on FELA provisions which state that if an employee's negligence plays any part in causing their injury - even as little as slight or trivial - then they are entitled to full damages without reduction due to their own contributory negligence. The decision clarified how liability is determined under FELA and affirmed that railroads could be held fully responsible for workplace injuries even when employee negligence played a role in causing those injuries.

In the dissenting opinion for Union Pacific Railroad Co. v. Sheehan, it was argued that the majority's decision to uphold a jury verdict in favor of an injured railroad worker under the Federal Employers' Liability Act (FELA) was incorrect because it failed to properly apply existing legal standards for causation and negligence. The dissent believed that there wasn't sufficient evidence presented at trial to prove that Union Pacific had been negligent or that such alleged negligence directly caused Mr. Sheehan’s injuries as required by FELA statute. They contended this case should have never reached a jury due to lack of substantial evidence on these key points, and thus, they disagreed with the majority's interpretation of what constitutes "sufficient" evidence in this context.