In Iron Mountain and Helena Railroad v. Johnson, the Supreme Court of the United States was asked to decide whether a railroad company was liable for damages caused by a train accident. The plaintiff, Johnson, was a passenger on the train when it collided with another train, resulting in serious injuries. Johnson sued the railroad company, claiming that the company was negligent in its operation of the train. The Supreme Court held that the railroad company was liable for Johnson's injuries. The Court found that the company had a duty to exercise reasonable care in the operation of its trains, and that it had breached this duty by failing to take proper precautions to prevent the accident. The Court also held that the company was liable for the damages caused by the accident, even though the company had not been negligent in its operation of the train. The Court's decision established that a railroad company is liable for damages caused by its negligence, even if the company was not negligent in its operation of the train. This decision has been cited in numerous cases since then, and has become an important precedent in the area of railroad liability.

In Iron Mountain and Helena Railroad v. Johnson, the 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 fencing along its right-of-way. The majority opinion held that the railroad company was not liable because it had acted with reasonable care in providing sufficient fencing around its tracks. Justice Field dissented from this decision, arguing that the railway should have been found negligent due to their failure to properly fence off their property which resulted in injury or death of livestock belonging to nearby landowners. He argued that since fences were necessary for safety purposes, they should have been provided regardless of cost or inconvenience; otherwise, those who suffered losses would be left without any remedy against the railway companies responsible for such accidents. Furthermore, he noted that if railways were allowed immunity from liability when they failed negligently neglected these duties then there would be no incentive for them take proper precautions and ensure public safety on their properties