Southern Pacific Co. v. Arizona Ex Rel. Sullivan, Attorney General

Mr. Chief Justice STONE delivered the opinion of the Court.

The Arizona Train Limit Law of May 16, 1912, makes it unlawful for any person or corporation to operate within the state a reilroad train of more than fourteen passenger or seventy freight cars, and authorizes the state to recover a money penalty for each violation of the Act. The questions for decision are whether Congress has, by legislative enactment, restricted the power of the states to regulate the length of interstate trains as a safety measure and, if not, whether the statute contravenes the commerce clause of the federal Constitution.

Although the commerce clause conferred on the national government powe to regulate commerce, its possession of the power does not exclude all state power of regulation. Ever since Willson v. Black-Bird Creek Marsh and Cooley v. Board of Wardens, it has been recognized that, in the absence of conflicting legislation by Congress, there is a residuum of power in the state to make laws governing matters of local concern which nevertheless in some measure affect interstate commerce or even, to some extent, regulate it. Thus the states may regulate matters which, because of their number and diversity, may never be adequately dealt with by Congress. When the regulation of matters of local concern is local in character and effect, and its impact on the national commerce does not seriously interfere with its operation, and the consequent incentive to deal with them nationally is slight, such regulation has been generally held to be within state authority.

In the application of these principles some enactments may be found to be plainly within and others plainly without state power. But between these extremes lies the infinite variety of cases in which regulation of local matters may also operate as a regulation of commerce, in which reconciliation of the conflicting claims of state and national power is to be attained only by some appraisal and accommodation of the competing demands of the state and national interests involved.

For a hundred years it has been accepted constitutional doctrine that the commerce clause, without the aid of Congressional legislation, thus affords some protection from state legislation inimical to the national commerce, and that in such cases, where Congress has not acted, this Court, and not the state legislature, is under the commerce clause the final arbiter of the competing demands of state and national interests.

Hence the matters for ultimate determination here are the nature and extent of the burden which the state regulation of interstate trains, adopted as a safety measure, imposes on interstate commerce, and whether the relative weights of the state and national interests involved are such as to make inapplicable the rule, generally observed, that the free flow of interstate commerce and its freedom from local restraints in matters requiring uniformity of regulation are interests safeguarded by the commerce clause from state interference.

The findings show that the operation of long trains, that is trains of more than fourteen passenger and more than seventy freight cars, is standard practive over the main lines of the railroads of the United States, and that, if the length of trains is to be regulated at all, national uniformity in the regulation adopted, such as only Congress can prescribe, is practically indispensable to the operation of an efficient and economical national railway system. On many railroads passenger trains of more than fourteen cars and freight trains of more than seventy cars are operated, and on some systems freight trains are run ranging from one hundred and twenty-five to one hundred and sixty cars in length. Outside of Arizona, where the length of trains is not restricted, appellant runs a substantial proportion of long trains. In 1939 on its comparable route for through traffic through Utah and Nevada from 66 to 85% of its freight trains were over 70 cars in length and over 43% of its passenger trains included more than fourteen passenger cars. In Arizona, approximately 93% of the freight traffic and 95% of the passenger traffic is interstate. Because of the Train Limit Law appellant is required to haul over 30% more trains in Arizona than would otherwise have been necessary.

The record shows a definite relationship between operating costs and the length of trains, the increase in length resulting in a reduction of operating costs per car. The additional cost of operation of trains complying with the Train Limit Law in Arizona amounts for the two railroads traversing that state to about $1,000,000 a year. The reduction in train lengths also impedes efficient operation. More locomotives and more manpower are required; the necessary conversion and reconversion of train lengths at terminals and the delay caused by breaking up and remaking long trains upon entering and leaving the state in order to comply with the law, delays the traffic and diminishes its volume moved in a given time, especially when traffic is heavy.

The unchallenged findings leave no doubt that the Arizona Train Limit Law imposes a serious burden on the interstate commerce conducted by appellant. It materially impedes the movement of appellant's interstate trains through that state and interposes a substantial obstruction to the national policy proclaimed by Congress, to promote adequate, economical and efficient railway transportation service. Enforcement of the law in Arizona, while train lengths remain unregulated or are regulated by varying standards in other states, must inevitably result in an impairment of uniformity of efficient railroad operation because the railroads are subjected to regulation which is not uniform in its application. Compliance with a state statute limiting train lengths requires interstate trains of a length lawful in other states to be broken up and reconstituted as they enter each state according as it may impose varying limitations upon train lengths. The alternative is for the carrier to conform to the lowest train limit restriction of any of the states through which its trains pass, whose laws thus control the carriers' operations both within and without the regulating state.

Although the seventy car maximum for freight trains is the limitation which has been most commonly proposed, various bills introduced in the state legislatures provided for maximum freight train lengths of from fifty to one hundred and twenty-five cars, and maximum passenger train lengths of from ten to eighteen cars. With such laws in force in states which are interspersed with those having no limit on train lengths, the confusion and difficulty with which interstate operations would be burdened under the varied system of state regulation and the unsatisfied need for uniformity in such regulation, if any, are evident.

If one state may regulate train lengths, so may all the others, and they need not prescribe the same maximum limitation. The practical effect of such regulation is to control train operations beyond the boundaries of the state exacting it because of the necessity of breaking up and reassembling long trains at the nearest terminal points before entering and after leaving the regulating state. The serious impediment to the free flow of commerce by the local regulation of train lengths and the practical necessity that such regulation, if any, must be prescribed by a single body having a nation-wide authority are apparent.

The trial court found that the Arizona law had no reasonable relation to safety, and made train operation more dangerous. Examination of the evidence and the detailed findings makes it clear that this conclusion was rested on facts found which indicate that such increased danger of accident and personal injury as may result from the greater length of trains is more than offset by the increase in the number of accidents resulting from the larger number of trains when train lengths are reduced. In considering the effect of the statute as a safety measure, therefore, the factor of controlling significance for present purposes is not whether there is basis for the conclusion of the Arizona Supreme Court that the increase in length of trains beyond the statutorty maximum has an adverse effect upon safety of operation. The decisive question is whether in the circumstances the total effect of the law as a safety measure in reducing accidents and casualties is so slight or problematical as not to outweigh the national interest in keeping interstate commerce free from interferences which seriously impede it and subject it to local regulation which does not have a uniform effect on the interstate train journey which it interrupts.

We think, as the trial court found, that the Arizona Train Limit Law, viewed as a safety measure, affords at most slight and dubious advantage, if any, over unregulated train lengths, because it results in an increase in the number of trains and train operations and the consequent increase in train accidents of a character generally more severe than those due to slack action. Its undoubted effect on the commerce is the regulation, without securing uniformity, of the length of trains operated in interstate commerce, which lack is itself a primary cause of preventing the free flow of commerce by delaying it and by substantially increasing its cost and impairing its efficiency.