Ex parte Railway Company is a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue an injunction against a railway company. The case arose when the state of Missouri sought to enjoin the St. Louis and Iron Mountain Railway Company from operating its trains on a certain stretch of track. The state argued that the railway company had failed to comply with certain state laws and regulations, and that the injunction was necessary to protect the public safety. The Supreme Court held that the state court did not have the authority to issue the injunction. The Court reasoned that the state court lacked jurisdiction over the railway company, as the company was a federally chartered corporation. The Court further held that the state court could not interfere with the federal government's exclusive power to regulate interstate commerce. The Court also noted that the state court's injunction would have interfered with the federal government's power to regulate the railway company's operations. In conclusion, the Supreme Court held that the state court did not have the authority to issue an injunction against the railway company. The Court reasoned that the state court lacked jurisdiction over the railway company, and that the injunction would have interfered with the federal government's exclusive power to regulate interstate commerce.

In Ex Parte Railway Company, the Supreme Court was asked to decide whether a state court had jurisdiction over an interstate railway company. The majority opinion held that the state court did not have jurisdiction and that only federal courts could hear cases involving interstate railroads. Justice Field dissented from this decision, arguing that states should be allowed to exercise their power of eminent domain over such companies in order to protect public safety and welfare. He argued that allowing states to do so would provide greater protection for citizens than if they were left solely under the control of federal authorities who may lack local knowledge or expertise on matters concerning transportation infrastructure within a particular state. Furthermore, he noted that Congress has never explicitly prohibited states from exercising their powers in this regard and thus it is up to each individual state as to how it wishes its laws regarding railroad regulation enforced within its borders.