delivered the opinion of the Court.
This is a suit for statutory penalties, instituted by the United States, charging respondent with the operation of four trains in violation of the Safety Appliance Act, 27 Stat. 531, as amended, 32 Stat. 943, 45 U. S. C. §§ 1, 6, 9. That Act requires every “trаin” moving in interstate traffic 1 to have power brakes on not less than 50% of *79 the cars (§§ 1, 9) — a requirement which the'Interstate Commerce Commission by regulation has increased to 85%. 49 CFR § 132.1. The penalties .are $100 for each violation. 2 § 6.
The'District Court renderеd judgment for respondent and the Court of Appeals affirmed by a divided vote.
Respondent has a “classification or assembly yard” in Hopewell, Virginia. Trains to and from Hopewell use it for breaking.up incoming trains and for assembling cars into outgoing trains. A- track extеnds from this “classification” yard for about two miles through the city. In this stretch the tracks make an interchange connection with another railroad and cross, at grade, fivé streets, two private roads and four traсks of another railroad. Nine spur tracks branch off these tracks to industrial sidings. About two miles from the “classification” yard are plants of the Allied Chemical & Dye Company and Continental Can Company.
The complaint charged four violations: First, moving a locomotive and 26 cars as a single' unit, without stops, from the track of Allied Chemical to the “classification” yard.' ' Second, moving a locomotive and 28 cars as a single unit, without stops, from the “classification” yard to the track of Allied Chemical. Third, moving a locomotive- and 29 cars as a single unit, without stops, from a track near Allied Chemical for about a mile to the interchange *80 track where the locomotive was detached, coupled to 20 additional cars, and then recoupled to the 29 cars. The 49 cars were then hauled, without stops, for about a mile tо the “classification” yard. Fourth, moving a locomotive and 23 cars as a single unit, without stops, from the “classification” yard to the track of Continental Can. 3
The meaning of the word “train” as used, in the Act has been before the Court four times. In
United States
v.
Erie R. Co.,
We think this case, judged by the principles announced in the earlier four,.was erroneously decided.
The end of each trip was characteristic of the usual freight run: cars were either received from a consignor -or delivered to the consignee. This was not “sorting, or selecting, or classifying” cars “involving coupling and uncoupling, and the movement of one or а few at a time for short distances’’ (Louisville & J. Bridge Co. v. United States, supra, at 538) nor any other type of movement that is comparable to “switching.” In three of the movements there was a run of two miles without stops. In one, there was one stоp to pick up additional cars ; but a mile run preceded that stop and another mile of uninterrupted travel followed it. The prior decisions make clear that it is immaterial that the run was nоt on the main "line but in a yard. The fact that switching preceded or followed these movements is likewise irrelevant to the statu *82 tory test. It may properly.be said there is no “train” in a true “switching” operation.. But when cars — at least in substantial number — are being received from consignors or delivered to consignees in an assembled unit of engine • and cars that moves a substantial distance, the opеration is intrinsically no different, for purposes of the Act, than a mainrline haul.
The District Court found that “The movements complained of would not have been less hazardous to employees -or thе public if air brakes had been coupled and used.” Yet it is not for courts to determine in particular cases whether this, safety measure is or is not needed. Congress determined the policy that governs us in applying the law. Traditionally, movements of assembled cars for substantial distances involved the hazards of, crossing public highways and the tracks of other lines with attendant risks to the • public. More imрortant, they involved risks to those who ride the trains, 4 párticu-larly the men who operate them. History showed that hundreds of workers had been injured or killed by the stopping of imbraked cars, by the operatiоn of hand brakes, and by. the use of hand couplers. This history, well known to Congress, 5 was the primary purpose behind *83 the legislation. The Act, therefore, should be liberally construed as a safety measure. Movements which, though miniature when compared with, main-line hauls, have the characteristics of the customary “train” movement and its attendant risks, are to be included.
Reversed.
Notes
Section. 1 provides, in relevant part:
“It shall be unlawful for any common carrier engaged in interstate cоmmerce by railroad to use on its line any locomotive engine in moving interstate traffic not ¿quipped with . . . appliances for oper *79 ating the train-brake system, or to run any train in such traffic that has not a sufficient number of cars in it so equipped with power or train brakes that the engineer on the locomotive drawing such train can control its speed without requiring brakemen to use the common hand brake for that purpose.”
The statute was amended August 14, 1957, to increase the penalty to $250 (71 Stat. 352, 45 U. S. C. (Supp. V) § 6).
Respondent since 1951 had used air brakes on the cars in these movements after insрectors of the Interstate Commerce Commission had advised that it was necessary to do so. But it discontinued the practice in 1956; justifying the discontinuance on the ground that switching movements were involvеd, that the use of air brakes caused a delay of about 40 minutes in each movement, and that the increased annual cost for the usé of air brakes was $30,000.
The title of the original Act described it as “An Aсt to promote the safety of employees arid travelers upon railroads . . .” etc. 27 Stat. 531.
See H. R. Rep. No. 1678, 52d Cong., 1st Sess., p. 3, where it is noted that for the years 1889 and 1890 “38 per cent of the total number of deaths and 46 per cent of the total number of injuries sustained by railway employés resulted while coupling cars or setting brakes.”
On page 7 of a report of a subcommittee submitted as a pаrt of S. Rep. No. 1930, 57th Cong., 1st Sess., the following statement of a witness appearing before the subcommittee was made: ;
“If only a portion of the equipped cars are operated, trainmеn are exposed to great danger ■ arising from the breakage of an air hose, or a coupling between the cars so braked, which causes an instantane *83 ous and extremely powеrful application of the power brakes, which causes the front cars in the train to quickly slacken speed and stop, and the other cars behind them, which are not braked, to rush forward against them, thus causing a severe shock, which often wrecks the train and jars the trainmen off and injures them, and' in some cases they fall under the wheels and are killed. If the brakes on all of thé cars were oрerated this would not be so, for the brakes would be applied equally all over the train, and the cars on! the rear end would slacken their speed just as quickly as those on the front end, and thus prеvent their running forward against the front cars and producing the shock just described. There is no -way for trainmen to escape these injuries; for they are still required by the companies to ride out on thе tops of trains, ^nd when.one of these shocks comes, it comes to them without warning, for the noise of the running train, together, with darkness at'night, prevents them from detecting any trouble ahead.
“Wrecks cаused in this way do not only cause injury to the trainmen on the train which is wrecked, but also on double-tracked roads the opposite track is immediately blocked, with wrecked cars, thus endangering not only the lives and limbs of trainmen, but passengers as well, who may be on trains approaching on the opposite track, which can not be stopped before striking the obstruction! I personally know of several bad wrecks of this character myself.”