In St. Louis, Iron Mountain & Southern Railway Company v. Southern Express Company, the Supreme Court of the United States was asked to decide whether a railroad company could be held liable for damages caused by a third-party express company. The express company had been hired by the railroad to transport goods, and the goods were damaged in transit. The railroad argued that it was not liable for the damages, as it had not been directly responsible for the damage. The Supreme Court held that the railroad was liable for the damages, as it had a duty to exercise reasonable care in selecting the express company. The Court reasoned that the railroad had a duty to ensure that the express company was competent and reliable, and that it had failed to do so. The Court also held that the railroad was liable for the damages, as it had a duty to inspect the goods and ensure that they were properly packaged and secured. The Court's decision established that a railroad company can be held liable for damages caused by a third-party express company, if the railroad fails to exercise reasonable care in selecting the express company or fails to inspect the goods and ensure that they are properly packaged and secured.

In St. Louis, Iron Mountain & Southern Railway Company v. Southern Express Company, the Supreme Court was tasked with determining whether a railroad company had to pay for damages caused by its negligence in failing to properly secure and transport goods belonging to an express company. The majority opinion held that the railroad was liable for these damages because it had assumed control of the goods when they were placed on board its train and thus owed a duty of care towards them until their delivery at their destination. Justice Field dissented from this decision, arguing that since there was no contract between the two companies regarding transportation services or any other matter related thereto, then no such duty existed and therefore liability should not be imposed upon the railroad company in question. He further argued that even if some sort of implied agreement did exist between them due to past dealings or custom, then it would only extend so far as providing reasonable care while transporting said goods but not necessarily full responsibility for any damage incurred during transit regardless of fault or negligence on behalf of either party involved