In the Union Pacific Railway Company v. O'Brien case of 1895, the U.S Supreme Court ruled in favor of Union Pacific Railway Company. The dispute arose when a train owned by Union Pacific collided with another train at a station, causing injuries to Mr. O'Brien who was an employee on one of the trains. He sued for damages alleging negligence on part of his employer -Union Pacific- arguing that they failed to provide him with a safe working environment as required by law. The court however found no evidence supporting this claim and held that it was not proven beyond reasonable doubt that Union's failure directly resulted in Mr.O’Brien’s injury or if he had contributed to his own harm through carelessness or lack of attention while performing his duties which could have prevented the accident from happening. This decision set precedence for future cases involving workplace accidents where employees must prove their employers' direct contribution towards any harm suffered during work hours before they can be compensated for damages.

The dissenting opinion in the case of Union Pacific Railway Company v. O'Brien argued that the majority's decision was incorrect because it failed to consider key aspects of contract law. The dissent emphasized that a contract is an agreement between two parties, and if one party fails to fulfill their obligations under this agreement, they should be held accountable for any resulting damages. In this case, the railway company had agreed to safely transport Mr. O'Brien's cattle but failed to do so due to negligence on their part which resulted in significant loss for Mr. O'Brien as several of his cattle died during transit. Therefore, according to the dissenting justices, Union Pacific Railway Company should have been found liable for these losses rather than being allowed by majority ruling not responsible based on technicalities related with bill lading conditions.