with whom the Chief Justice and Mr. Justice Reed concur, dissenting:
This case in its essentials can be reduced to simple terms; in effect, the question is whether the Interstate Commerce Commission acted unlawfully in holding unreasonable and discriminatory a proposed schedule of rates for the shipment of linoleum in trucks operated by members of appellants, associations of motor carriers. The facts are these. On linoleum shipments between points in New England, New Jersey, Delaware, Pennsylvania, and New York, and destinations in Iowa, Kansas, Minnesota, Missouri, Nebraska, and South Dakota, the members of the Eastern Central Motor Carriers Association charged 50% of first-class rates, minimum 20,000 pounds.1 This minimum is approximately the weight which conventionally is a truckload. Railroad rates on linoleum at this time were 70% of first-class for shipments of less than 30,000 pounds and 45% of first-class for those *213weighing at least 30,000 pounds—a conventional railroad carload.
By schedules filed to become effective August 24th, 1940, Eastern proposed rates of 47.5% of first-class, minimum 20,000 pounds, and 45% of first-class, minimum 30.000 pounds. The practical effect of this change would be to require a shipper who could send only 20,000 pounds of linoleum to pay a higher rate than one who could ship a consignment of 20,000 and 10,000 pounds. And two shippers, one with 10,000 pounds and the other with 20.000 pounds could combine their shipments at the lower rate, while a shipper of 10,000 pounds who could not conveniently join with others would have to pay the higher rate. These are the changes here in controversy. Upon the protest of the western trunk line rail carriers, later withdrawn when the appellants agreed that their 30,000 pound minimum rate would apply only on shipments “received at and transported from the point of origin, from one shipper in one day and on one bill of lading,” operation of the proposed schedules was suspended and Division 3 of the Commission held hearings to determine their validity. Upon their conclusion, Division 3 found that the proposed rates were reasonably compensatory, but that it was physically impossible to load 30,000 pounds of linoleum into a single unit of equipment, and that there was no showing that operating economies result when a 30.000 pound minimum shipment involving a truckload and fraction of another truckload is tendered. The Division thereupon concluded that a minimum weight greater than a truckload is unreasonable unless such a rate is justified by savings in cost, and ordered the proposed schedules cancelled to the extent found unjust and unreasonable. 31 M. C. C. 193.
This decision was fully reviewed by the entire Commission upon oral and printed arguments by the motor car-
*214riers, the linoleum shippers, and the National Industrial Traffic League, a group organized to promote the free interchange of commerce. The shippers and the Traffic League urged the Commission to leave the order of Division 3 undisturbed, while the motor carriers sought to justify the rates as legitimate means of meeting rail competition. The Commission agreed with Division 3 that the rates were unreasonable and held that the 30,000 pound minimum, based on no difference in transportation cost, would be discriminatory. 34 M. C. C. 641.
If the sole issue were whether there would be discrimination in favor of the 30,000 pound lot shipper as against the 20,000 pound lot shipper, clearly the Commission could find as it did, and the court below properly did not undo what the Commission did. 48 E. Supp. 432. Is there in fact more? The appellants contend that rail competition excuses and legalizes the discrimination beyond the Commission’s power to condemn. This Court does not yield to that claim, but it does hold that either the Commission must state with particularity why the evidence, of competitive conditions in this record is so vague and inadequate as to afford no justification for discrimination, or, in effect, requires the Commission to proceed with a full-dress investigation of the entire competitive relations between motor and rail carriers.
The Commission, on the basis of the evidence before it, concluded that “The competition between rail and motor carriers for linoleum traffic does not constitute such a dissimilarity in circumstances and conditions as to render legal the proposed discrimination.” Prior decisions of this Court surely do not require greater explication of the reasons on which the Commission’s conclusions are based. See Beaumont, S. L. & W. Ry. Co. v. United States, 282 U. S. 74, 86-87; United States v. B. & O. R. Co., 293 U. S. 454, 464-465. The Commission did not adopt an inflexible “principle that volume minimum rates *215will be allowed only when geared to a capacity loading which makes possible a real saving in costs of operation,” if its statement that “The extent to which competition between carriers may render discrimination and prejudice not unlawful must be decided upon the facts in each case” is to be accepted. Burke has said somewhere that he could not imagine English law without the law reports. Substantially the same considerations that call for giving reasons in rendering judicial decisions apply to the determinations of such agencies as the Interstate Commerce Commission. “We must know what a decision means before the duty becomes ours to say whether it is right or wrong.” See United States v. Chicago, M., St. P. & P. R. Co., 294 U. S. 499, 511. But we should not be more exacting of reports of the Interstate Commerce Commission explaining its orders than we are of the opinions of lower courts whose judgments come before us for review.
Nothing in this record calls for more explicitness than is ordinarily demanded. For nothing in the record requires the Commission to discuss the conceivable validity of proposed schedules which, aside from competitive conditions, are manifestly discriminatory. Such discriminatory rates were supported by a bare recital that railroad rates were nominally lower than motor carrier rates and that the business of one motor carrier had decreased. At the hearing before the Division, a representative of one motor carrier stated that the proposed rates were more than adequate to cover costs, that they did not vary substantially from rates imposed on the shipment of other comparable commodities, and that railroad competition had caused his company’s linoleum business to decline. He also testified that his firm competed for linoleum shipments with other motor carriers. This is the proposed justification for a rate differential concededly based on no difference in transportation cost or in service rendered and which therefore discriminates between those who ship 30,000 pound lots and *216those who ship 20,000 pound lots. And the record becomes even more barren when it is noted that the competitive conditions said to require adoption of the proposed discriminatory tariffs were not such as to prevent the rail carriers’ acquiescence in the adoption of the new schedule when, on appellants’ theory, the rail carriers had advantages intended to be mitigated by the new rates. The Commission found that either 47.5% or 45% was an allowable rate for either a 30,000 or 20,000 pound shipment—either rate “was within the zone of reasonableness.” It thereby permitted the motor carriers to compete on an entire equality with the rail carriers. But it forbade discrimination as between linoleum shippers equally placed. What the appellants really complain of is not that they cannot meet the railroad competition at the 45% rate on 30,000 pound lots, but that they cannot do so and yet collect 47.5% on lots of 20,000 pounds which are outside rail competition. Be that as it may, a mere arithmetic difference between railroad rates and motor carrier rates is quite blind. The rates themselves may not be at all revealing on competitive conditions; they may not tell what a shipper gets for his money and what he is paying for. That is, the quality of the service, the advantages of one type of service over the other, the availability of equipment, safety, labor cost, and many other factors may all give significance to the figures that figures themselves do not give.
The present ruling apparently imposes upon the Commission the duty of pursuing such complicated and far-reaching investigations every time a motor carrier rate that may have a relation to a railroad rate is found to be discriminatory in relation to another motor carrier rate affecting the same commodity. Such an investigation is an undertaking of vast scope involving consideration of factors which it would require an expert merely to catalogue. The different characteristics of rail and motor carrier serv*217ices, the economic wisdom of excluding motor carriers from large-bulk linoleum trade or limiting their participation in such trade, the availability of other commodity shipments to replace linoleum trade diverted to rail carriers, the availability of and cost of transporting commodities which might be used to fill the truck only partially loaded with linoleum—these are only a few of the factors which may become relevant. Compare III-B Sharfman, The Interstate Commerce Commission, pp. 572 et seq. The appellants introduced no evidence on the basis of which the Commission could intelligently weigh these considerations. To hold that the Commission must on its own initiative embark on such an investigation in a proceeding of this nature is to impose what may well be a crippling burden.
To speak more particularly of the task which the Commission now faces, it should be noted that Eastern files tariffs with the Commission for about 650 carrier members. A typical commodities clause from the carriers’ certificates of public convenience and necessity provides for the shipment of “General commodities, except those of unusual value, and except dangerous explosives, household goods as defined in Practices of Motor Common Carriers of Household Goods, 17 M. C. C. 467, commodities in bulk, commodities requiring special equipment, and those injurious or contaminating to other lading, over regular routes . . .” Thus it appears that the exceptions are few and the allowable shipments many. An investigation of the scope apparently required by the Court would entail a detailed study of the relations of the rate structures in a case merely involving the rates on specific commodities one to the other. If rail competition turns out to be actually detrimental to the successful operation of appellants’ linoleum business, the war-time load on the railroads might become relevant, and the Commission might have to decide whether the atypical circumstances at this time *218justify competitive discriminatory rates which might otherwise be unreasonable.
That the Commission is an expert body to which Congress has seen fit to commit the regulation of the intricate relationships between the various means of national transportation is a well-worn phrase which ought not to lose its significance in practice when the actions of the Commission come here for review. We should be very reluctant to define for the Commission the occasions which appropriately demand investigation of general transportation problems, and more particularly when a contest over the rate on a particular commodity included in a network of tariffs calls for such a general investigation. Surely it is within the special competence of the Commission to put on a discriminating carrier the duty of justifying by proof his plain discrimination as to a particular rate and not permit him to compel the Commission by a mere assertion to embark upon a far-flung inquiry. There are undoubtedly occasions when the Interstate Commerce Commission will undertake such an investigation in the public interest. But it ought not to be compelled to do so upon the occurrence, from an administrative point of view, of a more or less accidental filing of a tariff revision. When the carrier seeks to supplant a lawful rate, as is the case here, the burden is on it to supply all the essential information to justify the proposed new rate. § 216 (g), Part II of the Interstate Commerce Act, 49 U. S. C. § 316 (g). If it does not do so, it has failed to sustain the duty cast upon it by law, and the Commission in so finding has duly exercised its authority. The Commission’s dispositions of Molasses from New Orleans, La., to Peoria and Pekin, III, 235 I. C. C. 985 and Petroleum Rail Shippers’ Assn. v. Alton & Southern R., 243 I. C. C. 589, are entirely consistent, so far as that is relevant, with its order in this case,
“First-class” is used to designate the rates applied to a class of commodities. Percentages of a class rate are used as rates for designated commodities.