delivered the opinion of the court.
The Indiana statute requires _ railway companies to place secure grab-irons and hand-holds on the sides or ends of every railroad car, under a penalty of $100 fine to be recovered in a civil action.
In March, 1910, the Railroad Commission of the- State brought such a suit against the Southern Railway Company, alleging that the Company on February 24, 1910, had transported from Boonville, Indiana, to Milltown, *445 Indiana, a car which did not have the required equipment. The defendant filed an answer in which it denied liability under the state law inasmuch as on February 24, 1910, the Federal Safety Appliance Act imposed penalties for failing to equip cars with hand-holds and also designated the court in which they might be recovered. The Commission’s demurrer to the answer was sustained. The defendant refusing to plead further, judgment was entered against the ‘Company. That judgment was affirmed by the state court and the case was brought here by writ of error.
The car alleged to have been without the required equipment, though transporting freight between points wholly within the State of Indiana, was moving on a railroad engaged in interstate commerce and the Company was, therefore, subject to the provisions and penalties of the Safety Appliance Act. 27 Stat. 531, § 4.
Southern Railway
v.
United States,
The defendant in error insists, however, that the Railroad Company was also liable for the penalty imposed by the Indiana statute. In support of this position numerous cases are cited which, like
Cross
v.
North Carolina,
But the principle that the offender may, for one act, be prosecuted in two jurisdictions has no application where one of the governments has exclusive jurisdiction of the subject-matter and therefore the exclusive power to punish. Such is the case here where Congress, in the exercise of ‘its power to regulate interstate commerce, has legislated as to the appliances with which certain instrumentalities of that commerce must be furnished in order to secure the safety of employes. Until Congress entered that field the States could legislate as to equipment in such manner as to incidentally affect, without burdening interstate commerce. But Congress could pass the Safety Appliance Act only because of the fact that the equipment of cars moving on interstate roads was a regulation of interstate commerce. Under the Constitution the nature of that power is such that when exercised it is exclusive, and
ipso facto,
supersedes existing state legislation on the same subject. Congress of course could have “circumscribed its regulations” so as to occupy a limited field.
Savage
v.
Jones, 225
U. S.
501,
533.
Atlantic Line
v.
Georgia,
Without, therefore, discussing the many cases sustaining the right of the States to legislate on subjects which, while not burdening, may yet incidentally affect interstate commerce, it is' sufficient here to say that Congress has so far occupied the field of legislation relating to the equipment of freight cars with safety appliances as to supersede existing and prevent further legislation on that subject. The principle is too well established .to require argument. Its application may be seen in rulings in the closely analogous cases relating to state penalties for failing to furnish cars and to state penalties for retaining employés at work on Cars beyond "the time allowed by the Hours-of-Service Law.
In
St. L., Iron Mt. & S. Ry.
v.
Hampton,
The test, however, is not whether' the state legislation is in conflict with the details of the Federal law or supplements it, but whether the State had any jurisdiction of a subject over which Congress had exerted its exclusive control. The Safety Appliance Act having superseded the Indiana statute the judgment imposing the penalty-must be reversed, and the case- remanded for further proceedings not inconsistent with this opinion.
Reversed.
