with whom Mr. Justice Brennan and Mr. Justice Rehnquist join, concurring in the reversal of the injunction and dissenting from the affirmance of the remand to the Commission.
I dissent because the District Court erred both in holding that the Commission had inadequately explained the basis for its judgment and in suspending the new in-transit inspection tariff beyond the time the statute permits new rates to be suspended without a finding that they are unjust and unreasonable.
As to the latter, 49 U. S. C. § 15 (7) forbids the suspension of new freight rates for more than seven months without the requisite finding of unreasonableness by the Commission. Only the Commission may suspend in the first instance; and if the agency refuses to do so, the court is powerless itself to suspend. The Commission may postpone effectiveness of new rates for seven months, but if it does, the statute commands that, absent the appropriate order of the Commission within that period, “the proposed change of rate . . . shall go into effect . . . .” To permit the District Court nevertheless to extend this period seems to me to be flatly contrary to the will of Congress. I therefore cannot *829agree that, although the District Court has no statutory power to do so, it nevertheless retains sufficient power to enjoin the rates as “ancillary to the general equitable powers of the reviewing court, and protective of its jurisdiction.” Ante, at 819. As I see it, the District Court contravened the precepts of Arrow Transportation Co. v. Southern R. Co., 372 U. S. 658 (1963).
As for the remand to the Commission, there is somewhat more to be said. The Commission found, and it is not questioned by the District Court or by the majority here, that in-transit inspection of grain is not an essential part of transportation service but only ancillary to it; that the premarketing inspection of grain, in transit or otherwise, is no longer required by federal law; that in-transit inspection of grain has been the regular practice in Western territory, to some extent the practice in Southern territory, but not in Eastern territory; that the line-haul rates for grain in Western and Southern territories established by the railroads or prescribed by the Commission have provided one free in-transit inspection stop, but a separate charge for that service is the practice in Eastern territory; 1 and that, because of recent developments in-transit inspection is no longer an essential service *830for the orderly marketing of grain in Western and Southern territories. Furthermore, the unquestioned finding of the Commission was that the principal motivation for imposing a separate charge for in-transit grain inspection was not to increase railroad revenues through collection of the charge itself but to promote efficient utilization of freight cars by discouraging the practice of in-transit inspection which had proved extremely wasteful in terms of car utilization. The Commission finding, also undisturbed, was that the separately stated inspection fee would discourage the practice of in-transit inspection, would contribute to a more efficient utilization of freight cars, and hence help relieve the unquestioned grain-car shortage.
With these important preliminary findings and conclusions behind it, the Commission examined in detail the reasonableness of the separate charge being imposed for in-transit inspection of grain. Its conclusion was that the charge was reasonable, a judgment not overturned either here or in the District Court. Finally, the Commission noted that by the terms of the new tariff itself, separate in-transit inspection charges could not be collected where the combination of the new, separate charge and the existing line-haul rate exceeded the maximum reasonable level of grain rates established in Docket 17,000, pt. 7, Grain and Grain Products, 205 I. C. C. 301 (1934); 215 I. C. C. 83 (1936), as raised by subsequent general revenue increases. Docket 17,000, pt. 7, Rate Structure Investigation, was a major national effort, a comprehensive investigation of rates on agricultural products, and resulted, among other things, in the Commission’s prescribing maximum reasonable freight rate levels for movements of grain. Since that time, there have been general rate increases for revenue purposes, in the course of which the rates on grain and their structure as required by the 1934 and 1936 determinations have *831been given special attention. See, for example, Increased Freight Rates, 1967, 332 I. C. C. 280, 300 (1968).
Under the new tariffs now filed, as I have said, if the applicable line-haul rate on the particular grain movement involved is at the maximum reasonable level theretofore prescribed by the Commission in previous proceedings, no separate in-transit inspection charge is imposed or allowable, nor may the combination of the new charge and the existing line-haul rate collected by the railroad exceed the maximum allowable rate as previously determined. This is the key to understanding that, in approving the separate inspection charge, the Commission did not ignore its longstanding rule that railroads may not impose separate charges for an ancillary service previously furnished under a line-haul rate unless both the reasonableness of the separate charge and the line-haul rate are scrutinized. Transit Charges, Southern Territory, 332 I. C. C. 664, 683-684 (1968), is, for example a relatively recent restatement of the rule.2 The Commission thought this rule not controlling here because, in the first place, the magnitude of the task of justifying each one of a countless number of line-haul grain rates would, as a practical matter, prohibit the imposition of a separate in-transit inspection charge and so frustrate the important nonrevenue goal of discouraging in-transit inspection and so improving car utilization.
But, more fundamentally, the Commission in any event deemed the rule satisfied; for here the reasonableness of *832the line-haul rate was sufficiently examined and ensured by proof that the new charge was itself reasonable and by prohibiting its collection if the total cost of the grain movement — its line-haul charge plus the separate inspection charge — exceeded the maximum reasonable rate theretofore prescribed by the Commission, that is, the maximum reasonable rate the Commission had theretofore prescribed for both the transportation service and the privilege of in-transit inspection.
This approach seems straightforward and adequate. Keeping in mind that Docket 17,000, Part 7, as was customary in Western territory, prescribed rates for grain movements permitting one in-transit inspection without extra charge, let us assume, for example, that the maximum rate prescribed by the Commission for a particular grain movement with in-transit inspection privileges was 120. Assume further what is the recurring situation in the case before us — that the railroad is charging less than it may, say 100, for the grain movement with that privilege. The railroad then publishes a tariff under which the line-haul rate of 100 no longer entitles the shipper to in-transit inspection, and a separate charge of 20 is imposed on those who want that service. The line-haul charge plus the separate in-transit inspection charge does not exceed what the Commission has heretofore ruled the railroad may collect for both the transportation and the inspection service. This calculus seems to me an adequate basis for concluding that the line-haul rate of 100 is itself within the zone of reasonableness. If a railroad may charge 120 for a grain movement with in-transit inspection provided, and the inspection stop is proved reasonably worth 20, why should there also be occasion for considering the reasonableness of 100 as a line-haul rate and so proving again what the Commission previously found — that 120 is a reasonable charge for both services?
*833The District Court thought the Commission ignored Secretary of Agriculture v. United States, 347 U. S. 645 (1954), but I read that case far differently. There the Court, although being of the opinion that the Commission had not adequately explained why it was approving a separate charge without examining the legality of the line-haul rate, was careful to point out that the Commission was not precluded “from following a procedure fairly adapted to the unique circumstances of this case”; nor did the Court question “the Commission's power, under appropriate findings, to approve such unloading charges without pursuing one of these courses. In dealing with technical and complex matters like these, the Commission must necessarily have wide discretion in formulating appropriate solutions.” Id., at 652. That case does not stand for the rule that a separate charge for an ancillary service may in no circumstances be permitted without new proof in that proceeding of the reasonableness of the line-haul rate.
The prior decisions of the Commission relied upon by the District Court establish clearly enough that the Commission must be satisfied with the reasonableness of the line-haul rate as an exaction for the remaining services before approving a separate charge for a service previously covered by the line-haul rate. Transit Charges, Southern Territory, supra; Terminal Charges at Pacific Coast Ports, 255 I. C. C. 673 (1943); Reconsignment Case No. 3, 53 I. C. C. 455 (1919); Loading of Less-Than-Carload Freight on Lighters in Norfolk, Va., Harbor, 91 I. C. C. 394 (1924). In these cases, the carriers simply failed to carry their burden of proof.
The District Court also cited for this proposition Grand Forks Chamber of Commerce v. Great Northern R. Co., 321 I. C. C. 356 (1963), but the Commission in that case, see id., at 360-362, did precisely what it has done in this one: it approved a separate in-transit in*834spection charge in the case of so-called Group 3 rates where the line-haul rate and the new charge together were less than so-called Group 1 rates prescribed in Grain and Grain Products, 205 I. C. C. 301 (1934); 215 I. C. C. 83 (1936). See also Public Service Comm’n of North Dakota v. Great Northern R. Co., 340 I. C. C. 739 (1972) ; Alabama State Docks Dept. v. Alabama, T. & N. R. Co., 321 I. C. C. 347 (1963); Agsco Chemicals, Inc. v. Alabama G. S. R. Co., 314 I. C. C. 725 (1961).
Neither do I understand why the majority is comforted by the opinion in Cincinnati N. O. & T. P. R. Co. v. United States, Civil Action No. 6992 (SD Ohio, Jan. 12, 1970), in which the District Court affirmed, but on very limited grounds (grounds that would save the cases before us now), the Commission’s disallowance of a separate transit charge for cotton movements but disapproved the stringent standard by which the Commission required the railroads to prove the reasonableness of the resulting line-haul rate. The District Court restated the prevailing rubric:
“The question here is what should the carrier be paid for a service which it has been rendering, and has been charging for, and has been paid for (one knoweth not what) which it proposes to separate and charge separately for. Both the courts and the Commission have consistently held that what is a just and reasonable rate for the service to be separated and charged for separately cannot be determined by examining only the typical questions of cost, etc., with respect to the separate service. On the contrary, the typical questions must be directed to the overall or combined picture so that one may conclude (a) that the rate for the separated service, looked at by itself in the light of the applicable questions, is just and reasonable; and (b) that the *835remaining rate for the services, sans the separated service, is not rendered unjust or unreasonable.”
The District Court continued:
“Whether the examination is in terms of 'what portion of the line-haul rate represented the rate for the service to be separated/ or whether the search in terminology is for the answer to this question: Does the new aggregate rate, composed oj line-haul plus transit rates represent a just and reasonable rate for all of the services (the aggregate of the severed and the nonseveredj — the principle is the same.” (Emphasis added.)
A few paragraphs later, the court repeated the same alternate approach. This Court affirmed the District Court summarily. 400 U. S. 932 (1970). In the litigation now before us the total of the line-haul rate and the separate in-transit charge will in no case exceed what the Commission has heretofore found to be a reasonable charge for the aggregate service.
The maximum permissible rates for grain movements with in-transit inspection privileges were established some years ago, it is true, but they have been subject to repeated examination upon the occasions of general rate increases and, as this litigation itself shows, they are far from dead letters from the standpoint of either the railroads or the Commission. They remain the foundation of the Commission’s opinion as to what just and reasonable grain rates are with in-transit privileges furnished by the railroad. I see no reason for now disagreeing with the Commission’s judgment that the reasonableness of a line-haul rate lower than the maximum allowable has been sufficiently re-examined to permit imposition of a separate in-transit inspection charge, in itself found reasonable, when it is also determined that the existing *836line-haul rate and the new inspection charge together total less than the maximum Commission-prescribed rate for the two services combined. Surely this presents an inadequate occasion or context in which to frustrate what the Commission found to be a promising effort to solve a critical problem — the freight car shortage — by seeking to deter a wasteful practice not indispensable or even, in the Commission’s view, unusually important to the orderly marketing of grain under modern conditions.
For these reasons, I respectfully dissent.
The Commission noted :
“It is again emphasized that the major impact of the proposal under consideration will be on the movement of grain in the western district. Most inspections occur in this territory. There is presently effective a separate charge for this service in the East. A substantial increase in those charges will result, however, if the proposed charges are permitted to become effective. The number of in-transit inspections in the South is limited and take place chiefly at the ports on export grain tonnage. There is little, if any, opposition to establishment of the charges in southern territory. Practically all of the controversy is concerned with establishment of the separate charge for the first inspection of grain within the western district.” 339 I. C. C. 364, 385.
The Commission’s order was sustained, on other grounds, in Cincinnati, N. O. & T. P. R. Co. v. United States, Civil Action No. 6692 (SD Ohio, Jan. 12, 1970), aff’d, 400 U. S. 932 (1970). The District Court sustained the Commission on the basis that the proposed increase in charges might well result in a substantial diversion of the considered traffic, with a diminution, rather than an increase, in revenues. In the present case, the Commission noted: “Similar conclusions are not warranted here.”