Pacific Railroad v. Ketchum was a United States Supreme Court case that dealt with the issue of whether a railroad company was liable for damages caused by a train accident. The plaintiff, Ketchum, was a passenger on a train operated by the defendant, Pacific Railroad. Ketchum was injured when the train derailed due to a broken rail. Ketchum sued the railroad for damages, claiming that the railroad was negligent in maintaining the track. The Supreme Court held that the railroad was liable for Ketchum's injuries. The Court reasoned that the railroad had a duty to maintain the track in a safe condition and that it had breached this duty by failing to inspect and repair the broken rail. The Court also held that the railroad was liable for Ketchum's damages, even though the railroad had not been negligent in operating the train. The Court's decision in Pacific Railroad v. Ketchum established that a railroad company is liable for damages caused by a train accident, even if the railroad was not negligent in operating the train. This decision has been cited in numerous subsequent cases involving railroad liability.

In Pacific Railroad v. Ketchum, the United States Supreme Court was asked to decide whether a railroad company could be held liable for damages caused by its negligence in failing to provide adequate safety measures on its property. The majority opinion of the court found that the railroad had not breached any duty owed to passengers and thus could not be held liable for their injuries. Justice Field dissented from this decision, arguing that it was well established law at the time of this case that railroads were required to use reasonable care when transporting passengers and goods over their lines and should therefore be responsible for any harm resulting from their failure to do so. He further argued that if railroads were allowed immunity from liability in such cases, they would have no incentive whatsoever to ensure passenger safety or take other necessary precautions while operating trains on their tracks.