Mr. Justice Fortas
delivered the opinion of the Court.
These cases again bring before us problems arising from the program to merge the Pennsylvania and New York Central railroads and related problems proceeding from an Interstate Commerce Commission order that certain railroads be included in the Norfolk & Western (N & W) system. The merger and the inclusion orders are part of a vast reorganization of rail transportation implementing the congressional policy of encouraging consolidation of the Nation’s railroads into a “limited number of systems.” Section 407 of the Transportation Act of 1920, amending § 5 (4) of the Interstate Commerce Act, 41 Stat. 481. That policy has been with us, in one form or another, for more than 45 years. The original idea of the 1920 Act, that the ICC would formulate a national plan of consolidation, proved unworkable. It ran into heavy opposition from carriers and eventually had to be abandoned. The 1920 Act was replaced by the Transportation Act of 1940, 54 Stat. 898. Section 5 (2)(b) of the Interstate Commerce Act, as amended by the 1940 Act, 54 Stat. 906, 49 U. S. C. §5 (2)(b), governed the Commission’s examination of the present transactions. Under the 1940 Act, the initiation of [493]*493merger and consolidation proceedings is left to the carriers themselves, and the Commission possesses no power to compel carriers to merge. However, the congressional directive for a limited number of railroad systems has not been changed. The only change has been in the means of achieving that goal. See generally St. Joe Paper Co. v. Atlantic Coast Line R. Co., 347 U. S. 298, 315-321 (Appendix) (1954).
The Pennsylvania and the New York Central dominate rail transportation in the Northeast. Their freight operations extend over some 20,000 miles of road in 14 States and Canada. They are the two largest passenger carrying railroads in the United States. In 1965 their combined operating revenue surpassed $1,500,000,000 and their combined net income was more than $75,000,000. As independent lines, Pennsylvania and New York Central are, to some extent, in direct competition for rail traffic. There are 32 urban areas in which the two lines are in competition with each other and in which no other rail facilities are available. The two roads operate at 160 common points or junctions and have a substantial amount of parallel trackage and routes. The proposed merger which the ICC has approved contemplates the unification of these vast roads and, as time goes on, the rationalization and elimination of some of the dual facilities and services in various areas and in various respects. The merger will result in “enormous savings in transit time.” It is estimated that in eight years, the savings in expense will amount to more than $80,000,000 annually. See Baltimore & Ohio R. Co. v. United States, 386 U. S. 372, 379-381 (1967).
At the same time the combination of these two roads will directly and adversely affect various smaller railroads in the service area because of the more effective competitive service that the combined system will offer and [494]*494because of the tendency of the combined roads, unless restrained by law, to favor their own system rather than to share traffic by interchange with nonsystem roads.
In brief, the antecedents of the issues before us are as follows: the Penn-Central merger has been under consideration by the parties and the Commission for about 10 years. It was preceded by the vast N & W-Nickel Plate merger, which the Commission approved in 1964. That transaction, which, it is anticipated, will eventually produce savings for the N & W system of over $29,000,000 annually, resulted in a large rail network covering some 7,000 miles of track and extending in the north from Des Moines and Kansas City to Buffalo and Pittsburgh, and in the southern tier from Cincinnati to Norfolk. See Norfolk & Western Railway Co. and New York, Chicago & St. Louis Railroad Co.—Merger, etc., 324 I. C. C. 1 (1964). The transaction was not presented to this Court for review.
In 1962 the parties to the Penn-Central transaction signed an agreement of merger including 36 rail carriers. The merger agreement did not include the New York, New Haven & Hartford Railroad (NH), although that road requested inclusion.
Following the merger agreement, the parties submitted the proposal to the Commission for approval under § 5 (2) of the Interstate Commerce Act. Exhaustive hearings were held in which States, municipalities, railroads, shippers, and public bodies — some 200 parties in all — took part. The Commission's own staff participated extensively as did the Department of Justice acting for affected interests of the United States other than the regulatory functions of the Commission. All participants, with relatively minor exceptions to which we shall later advert, agreed that the merger itself would be in the public interest. There were sharp differences, however, with respect to certain issues. These primarily concerned the [495]*495provisions to be made for three smaller lines affected by the proposed merger: the Erie-Lackawanna (E-L), Delaware & Hudson (D & H), and Boston & Maine (B & M) railroads. The Commission approved immediate consummation of the merger, subject to a reservation of jurisdiction to establish protective provisions for the three roads. Pennsylvania Railroad Co.—Merger—New York Central Railroad Co., 327 I. C. C. 475 (1966). Its order was approved by a three-judge court in the Southern District of New York. Erie-Lackawanna R. Co. v. United States, 259 F. Supp. 964 (1966).
At the last Term of Court, we reversed. We noted that the Commission itself had found that the survival of the E-L, D & H, and B & M was essential to the public interest and that these roads would be so seriously affected by the competition of the merged company that they might not be able to survive unless adequate protective arrangements were made. In these circumstances we concluded that the Commission should have determined the means to preserve the "protected roads,” on both an interim and a permanent basis, before permitting consummation of the merger. We expressly stated that we were not passing upon the validity of the merger or the "peripheral points posed by the various parties.” Baltimore & Ohio R. Co. v. United States, supra, at 378.
The Court noted that in 1965 each of the three “protected roads” had filed applications for inclusion in the N & W system, and that these were pending before the Commission in the N & W-Nickel Plate merger case pursuant to the Commission’s continuing jurisdiction over those proceedings. We further noted that the Commission, pursuant to its power under § 5 of the Act to require as a condition of approval of a merger that other railroads be included in the merger, had obligated the merged N & W system to include the E-L, D & H, [496]*496and B & M if the Commission should so direct, upon such equitable terms as the Commission might prescribe. We stated that if the three protected roads were ordered to be included in the N & W system, “such action would provide the solution to the problem of the necessary and indispensable protection to the three railroads that the Commission found prerequisite to the merger.” 386 U. S., at 390.
In accordance with our remand of the Penn-Central merger case, the Commission conducted further proceedings in the N & W case on the pending petitions of the three roads. On June 9, 1967, it issued its decision to the effect that “inclusion of the petitioners in the N & W system is preferable to their inclusion in the Penn-Central,” and ordered N & W to acquire the stock of the three roads on prescribed terms. Norfolk & Western Railway Co. and New York, Chicago & St. Louis Railroad Co.—Merger, etc., 330 I. C. C. 780, 796 (1967). At the same time, in the remanded Penn-Central merger proceedings, the Commission reconsidered certain protective conditions it had previously devised to aid the three roads, imposed amended protective conditions to operate in the interim between consummation of the Penn-Central merger and the protected lines’ inclusion in a major railroad system,1 and again authorized the immediate consummation of the Penn-Central merger. Pennsylvania Railroad Company—Merger—New York Central Railroad Company, 330 I. C. C. 328 (1967).
On July 3, 1967, on application of parties opposing the Commission’s merger order, the three-judge District Court for the Southern District of New York enjoined implementation of that order pending the decision of that court on review. Actions were also filed by sev[497]*497eral parties in the same court to set aside the order of the Commission requiring the N & W to include the three protected roads in its system. Suits challenging both the merger and inclusion orders were instituted in other courts, but were stayed so as to permit orderly disposition of the basic issues in the Southern District of New York.2 After expedited proceedings in that court, all complaints attacking the merger and the inclusion orders were dismissed3 and the decisions of the Interstate Commerce Commission in both the merger and the inclusion proceedings were sustained. 279 F. Supp. 316. Various of the parties then sought relief in this Court. Because of the importance and urgency of the matter, we granted a further stay of the merger order, consolidated all proceedings that were before us relating to the merger and inclusion decisions, and expedited consideration thereof. See post, p. 946.
We have before us nine appeals, on behalf of 17 parties, from the decision of the District Court. Also docketed are two related petitions for mandamus or certiorari to the District Court for the Middle District of Pennsylvania, and one appeal from that court.
[498]*498The particular contentions urged upon us, in this multiplicity of proceedings, are many and varied. In general, however, the issues may be articulated as follows: Has the mandate of this Court been fulfilled, in that appropriate provision has now been made for the three smaller roads? Are the terms of the order providing for inclusion of the protected roads in the N & W system fair and equitable and in the public interest? Did the District Court err in refusing to enjoin consummation of the Penn-Central merger? Has adequate provision been made for resolution of the “peripheral” issues presented by the parties, which would not be foreclosed by a decision authorizing the consummation of the merger and inclusion of the protected roads in the N & W?
I. The Merger Decision.
A. IN GENERAL.
Most of the parties before us are in accord that the merger is in the public interest and should be consummated as promptly as possible. Those urging immediate consummation before this Court include the Department of Justice and the Commission, the States of Pennsylvania, Connecticut, Rhode Island, New York, Massachusetts, and New Jersey; the Railway Labor Executives’ Association; the trustees of the NH; the Pennsylvania and New York Central railroads; B & M; and, in substance, the E-L, D & H, and N & W and its allies. While this consensus has reduced the attacks upon the merits of the merger to a minimum, considering the vast size and implications of the transaction, we must nevertheless address ourselves to the basic merits of the merger as well as to the specific objections that are before us.
With respect to the merits of the merger, however, our task is limited. We do not inquire whether the merger satisfies our own conception of the public in[499]*499terest. Determination of the factors relevant to the public interest is entrusted by the law primarily to the Commission, subject to the standards of the governing statute. The judicial task is to determine whether the Commission has proceeded in accordance with law and whether its findings and conclusions accord with the statutory standards and are supported by substantial evidence. See, e. g., Illinois C. R. Co. v. Norfolk & W. R. Co., 385 U. S. 57, 69 (1966).
Section 5 of the Interstate Commerce Act, as amended by the Transportation Act of 1940, 54 Stat. 905, 49 U. S. C. § 5, sets forth the national transportation policy that is to guide the Commission in its scrutiny of mergers proposed by railroads. The Commission is to approve such proposals, pursuant to the terms of § 5 (2) (b) of that Act, when they are made upon just and reasonable terms and are “consistent with the public interest.” In reaching its decision, the Commission is to give weight to a number of factors, such as: “(1) The effect of the proposed transaction upon adequate transportation service to the public; (2) the effect upon the public interest of the inclusion, or failure to include, other railroads in the territory involved in the proposed transaction; (3) the total fixed charges resulting from the proposed transaction; and (4) the interest of the carrier employees affected.” 49 U. S. C. § 5 (2)(c).
We find no basis for reversing the decision of the District Court that the Commission’s approval of the merger is in compliance with law and the statutory standards, and is based on adequate findings supported by substantial evidence. We shall first discuss considerations which are basic to the statutory standards, and we shall then turn to certain particular objections which have been made.
It is, of course, true that the policy of Congress, set forth in the Transportation Act, to consolidate the rail[500]*500roads of this Nation into a “limited number of systems” is a variation from our traditional national policy, reflected in the antitrust laws, of insisting upon the primacy of competition as the touchstone of economic regulation. Competition is merely one consideration here. See Seaboard Air Line R. Co. v. United States, 382 U. S. 154 (1965). This departure from the general and familiar standard of industrial regulation emphasizes the need for insistence that, before a rail merger is approved, there must be convincing evidence that it will serve the national interest and that terms are prescribed so that the congressional objective of a rail system serving the public more effectively and efficiently will be carried out. Obviously, not every merger or consolidation that may be agreed upon by private interests can pass the statutory tests.
Examination of the record and of the findings in the present case, however, satisfies us that the Commission has properly and lawfully discharged its duties with respect to the merits of the merger. In these elaborate and lengthy proceedings the Commission has considered evidence tendered by others and compiled by its own staff. Upon the aggressive suit of parties representing conflicting interests, it has analyzed every pertinent aspect of the merger and the inclusion order. It has weighed conflicting viewpoints on all of the fundamental issues and many that are tangential. As the Commission concluded, the evidence before it, with negligible exceptions, attested to the probability of significant benefit from the merger, not only to the railroads and their investors, but also to shippers and the general public.
The Commission carefully considered the implications of the fact that the Pennsylvania and the New York Central, as individual systems, have operated at a profit, and that there are reasonably good prospects for a continuation of such operation. But it was impressed by the fact [501]*501that, as individual systems, these profits are not sufficient to put the roads in a position to make improvements important to the national interest, including the maintenance of services which, although essential to the public, are not self-supporting, and furnishing assistance to other roads serving public needs in their general territory. The Commission emphasized that the merger would enable the unified company to “accelerate investments in transportation property and continually modernize plant and equipment . . . and provide more and better service.” 327 I. C. C. 475, 501-502. And it pointed out that only by permitting the merger would it be possible for the Commission to compel Penn-Central to come to the rescue of the New Haven, as we shall describe.
With respect to the lessening of competition where it now exists between the roads to be merged, the Commission pointed out that it will retain continuing power over reductions of service and facilities which are not specifically approved in the merger plans. Such consolidations and abandonments will have to be presented to the Commission for its approval and may be subjected to public criticism and hearings and to conditions or disapproval. It also noted that the rail service by the merged company will remain subject to vigorous competition from other roads, including the N & W and the C & O-B & 0 systems, and from motor, water, and air carriers. The Commission summarized some of the factors which would act as a restraint upon the merged company as follows:
“The power of shippers to direct the routing, the availability of numerous routes in a dense network of interline routes, the influence of connecting carriers in preventing a deterioration in service on the joint routes in which they participate, the growing strength of the N & W and C & O-B & 0 systems, [502]*502all stand to provide a check against any abuse of economic power by the merged applicants.” 327 I. C. C., at 514.
Considering the record, and the findings and analysis of the Commission, we see no basis for reversal of the District Court's decision that the Commission’s “public interest” conclusions are adequately supported and are in accordance with law. We find no basis, consonant with the principles governing judicial review, for setting aside the Commission's determination, approved by the District Court, that the “public interest” directives of the governing statute have been reasonably satisfied: that the transaction is likely to have a beneficial and not an adverse effect upon transportation - service to the public; and that, as we shall discuss, appropriate provisions have been made with respect to other railroads that are directly affected by the merger.
B. OBJECTIONS OP CERTAIN PENNSYLVANIA INTERESTS.
The only objectors in this Court to the public interest findings with respect to the merger are certain interests in the State of Pennsylvania. Appeal No. 835 was taken by the City of Scranton and Milton J. Shapp, a stockholder in the Pennsylvania Railroad Company. These parties filed complaints in the Southern District of New York challenging the Commission’s original merger decision. After this Court’s remand last Term, they were ordered by the District Court to file supplemental complaints. They declined to comply because, having intervened as plaintiffs in a proceeding challenging the merger in the Middle District of Pennsylvania, they chose to rely upon their asserted right to challenge the Commission’s merger and inclusion decisions in the Pennsylvania action. After several warnings, their complaints in the New York court were dismissed, with prejudice.
The action in the Middle District of Pennsylvania, in which Shapp and Scranton intervened, was filed by the [503]*503Borough of Moosie on June 26, 1967, to set aside the Commission’s orders, entered after our remand, approving the Penn-Central merger and the inclusion of the three protected roads in the N & W system. The Pennsylvania court stayed the Moosie proceeding by order of July 11, 1967, on the request of the United States and the Commission, for the sound purpose of preventing a multiplicity of litigation regarding the Commission’s merger and inclusion decisions. Cf. Kansas City Southern R. Co. v. United States, 282 U. S. 760 (1931). Petitions for mandamus or certiorari, on behalf of Moosie (No. 663, Misc.) and Scranton and Shapp (No. 664, Misc.), seeking to challenge the stay of proceedings entered by the Pennsylvania court, have been filed in this Court. Since it now appears that the Middle District of Pennsylvania has dissolved its stay and commenced hearings, it would be pointless for us to review the stay order. Accordingly, the petitions for mandamus or certiorari are dismissed as moot.
Scranton, Shapp, and Moosie attack the Commission’s merger and inclusion decisions along a broad front and claim error in the Commission’s basic findings that the Penn-Central merger and inclusion of the protected lines in N & W are in the public interest. The thrust of this argument is that the Commission failed to consider or properly to evaluate the adverse effect of the Penn-Central merger, considered in fight of the order requiring inclusion of the three protected roads in the N & W system, upon certain affected communities in the State of Pennsylvania. We do not agree. In its April 6, 1966, opinion approving the Penn-Central merger, the Commission examined the arguments made by participating communities in great detail and stated that the “contentions regarding the adverse effect of the merger on Pennsylvania’s economy are not substantiated by the evidence. On this record, the prospects clearly import that the [504]*504merger will benefit rather than harm the Commonwealth.” 327 I. C. C. 475, 492. At the time it made this finding, the Commission was committed to the proposition enunciated in the April 6, 1966, opinion, that the three protected roads would be included in one of the larger systems because of their inability to survive as independent lines. This Court in its decision last Term emphasized the importance of such inclusion. The Commission’s conclusion that the net result of the merger would be beneficial to the State of Pennsylvania is bolstered by the strong position taken by the State in this Court that the decision of the District Court for the Southern District of New York should be affirmed.
As we discuss, infra, apart from the general and theoretical argument that the Penn-Central merger and the inclusion of the three roads in the N & W system may harm some Pennsylvania interests, complainants’ fears of specific injury resulting from reduction of competition by specific curtailments of service now provided by the three protected lines may be asserted in appropriate proceedings when such curtailment is specifically proposed.
All other complaints of these parties relate broadly and generally to the fundamental and underlying economic problems that are involved in the merger and inclusion decisions: for example, the anticompetitive consequences of these decisions and the financial situation and prospects of the Pennsylvania and New York Central as independent lines. They were all the subject of extensive evidence and were analyzed at length by the Commission. In dismissing the complaints of Scranton and Shapp for failure to go forward, Judge Friendly noted that “[wjhile we entertain no doubt of the sufficiency of this [procedural] ground, we think it well to add that... we find no merit in the complaints of Shapp and The City of Scranton.” The court remarked that, for the most part, “the attacks [of Scranton and Shapp] simply [505]*505represent disagreement with procedural and policy determinations which Congress has committed to the Commission.” 279 F. Supp., at 326, n. 6. We find no reason to reverse the judgment of the District Court for the Southern District of New York for dismissing the complaints of Scranton and Shapp for failure to prosecute, or to set aside its conclusions as to the lack of merit of their claims, particularly in light of the limited function of judicial review of decisions such as those now before us and the opportunity open to them to challenge proposals which may be made for specific curtailment of service.
Scranton and Shapp, like the Borough of Moosic, wish now to go forward with their complaints in the Middle District of Pennsylvania, in which they seek an injunction against consummation of the Penn-Central merger and the effectiveness of the inclusion order. But Shapp and ScrantoP were parties to the New York proceedings and the Borough of Moosic had an adequate opportunity to join in the litigation in that court following the stay of proceedings in the Middle District of Pennsylvania. As we noted, supra, n. 2, all district courts in which actions to review the Commission’s findings or for in-junctive relief were filed continued their proceedings in deference to the New York court. All parties with standing to challenge the Commission’s action might have joined in the New York proceedings.4 In these circumstances, it necessarily follows that the decision of the New York court which, with certain exceptions, [506]*506we have affirmed, precludes further judicial review or adjudication of the issues upon which it passes. While it is therefore no longer open to the parties to challenge the Commission’s approval of the Penn-Central merger and inclusion of the three protected lines in N & W, or its order that immediate consummation of the merger should be permitted, any claims for specific relief, such as particularized objections which may arise from specific proposals for consolidation or reduction of facilities or services, are unaffected by the decision in the present cases. Claims not precluded by the present decision may be pursued before the Commission or in the courts or both, as may be appropriate. This applies to Shapp, to the City of Scranton, and to the Borough of Moosic as well as to any other affected interests. The proceedings in the Middle District of Pennsylvania are not before us, except as we have dismissed as moot the petitions challenging that court’s stay of its proceedings, and it will be the task of that court to determine the effect of the present decision upon the proceedings before it. Scranton, Shapp, and Moosic may, of course, seek such relief, if any, in that court as may be available and appropriate in light of our decision herein.
Finally, we must mention the City of Pottsville, which has appealed to this Court (No. 433). Pottsville’s request to intervene in the Moosic action, upon a complaint similar to that of Moosic, was denied by the Middle District of Pennsylvania. Like Moosic, Pottsville had the opportunity — which it failed to seize — to litigate in the Southern District of New York. It appears that a principal basis for denial of Pottsville’s request to intervene was the objection interposed by the United States and that this objection will, after our decision in the instant cases, be withdrawn. Upon this representation by the United States, without reference to or any attempt to consider the scope or content of the [507]*507action in which intervention is sought, or the issues, if any, which may remain for adjudication in that proceeding, we vacate the decision of the District Court for the Middle District of Pennsylvania denying intervention and remand Pottsville’s case to that court for further consideration in light of our decision today.
C. OBJECTIONS OF THE NEW HAVEN’S BONDHOLDERS.
Two appeals, Nos. 830 and 831, have been taken on behalf of bondholders of the New York, New Haven and Hartford Railroad Company (NH). Since 1961 the NH has been in reorganization proceedings under § 77 of the Bankruptcy Act, 11 U. S. C. § 205. Despite the shelter of the bankruptcy court, it has been on the verge of financial collapse with the attendant risk to continuance of its rail service. The Commission has found that passenger as well as freight service by the NH is a national necessity and that termination of either would lead to distress in Connecticut, Massachusetts, and Rhode Island, and would severely damage New York City and the Nation generally. See New York, New Haven & Hartford Railroad Co., Trustees. Discontinuance of All Interstate Passenger Trains, 327 I. C. C. 151 (1966).
The NH competes in a relatively small part of its service area with the New York Central; but in the NH’s financial condition, diversion of even a small amount of the Pennsylvania’s connecting traffic from the NH to the Central would inflict consequential injury. Even without reference to the hazard of such diversion, inclusion of the NH in the Penn-Central combination is the only possibility that has been advanced by any of the parties — including the complaining bondholders — for continued operation of NH, short of the sheer speculation that the States concerned or the Federal Government might take over the road and its operations.
[508]*508In June 1962, with permission of the bankruptcy court, the New Haven’s trustees requested the ICC to make provision under § 5 (2) (d) of the Act for its inclusion in the proposed Penn-Central merger. When the Commission first considered the merger, it stated that “we will require all the New Haven railroad [both passenger and freight operations] to be included in the applicants’ transaction”; and in its initial report it provided that “our approval of the merger is conditioned upon such inclusion.” 327 I. C. C., at 524, 527. It required that the parties to the merger irrevocably stipulate that they would consent to inclusion upon such terms as might be agreed between the NH and the merger parties or, failing this agreement, upon such terms as the Commission might prescribe with the approval of the bankruptcy court. 327 I. C. C., at 553.
The trustees of the NH and the two companies conducted lengthy negotiations and finally arrived at an agreement as to inclusion terms dated April 21, 1966, amended October 4, 1966. In July 1967 the NH bankruptcy court warned that New Haven’s cash depletion was “so serious that, if the present rate of loss continues, there will be insufficient left by late September to meet the payroll.” Subsequent improvement of cash position permitted amendment of this dire prediction so that it was expected that operation could be financed to January 1968.
The Commission on August 3, 1967, directed the negotiation of a lease between the New Haven trustees and Penn and Central, to be “immediately available upon consummation of the Penn-Central merger.” The parties, however, reported that preparation of a lease in time to meet the New Haven’s needs was not possible. Thereupon, the Commission ordered a hearing as to whether a lease, loan, or other arrangement should be made to [509]*509assure the NH’s continued operation until its acquisition by Penn-Central. On November 21, 1967, the Commission issued an order, subject to the approval of the bankruptcy court, providing (a) terms for the inclusion of the New Haven in the Penn-Central system upon effectuation of the Penn-Central merger; (b) for the Penn-Central to lend $25,000,000 to the New Haven over a three-year period in return for trustees’ certificates; and (c) for the Penn-Central to bear 100% of the operating losses of the New Haven during the first year after the merger, 50% in the second, and 25% in the third, subject to a ceiling of $5,500,000 in each year on the total amount that Penn-Central could be required to absorb and subject to termination upon transfer of the New Haven assets. Acceptance of these terms by Penn and Central is a required condition of approval of their merger. The Commission has retained jurisdiction “for the purpose of making such further order or orders in these proceedings as may be necessary or appropriate.”
The merits of these provisions are not before us. They have not been reviewed by the bankruptcy court or by a statutory district court under the applicable statute. The New Haven trustees and the States of Connecticut, Massachusetts, Rhode Island, and New York, as well as the United States, have filed briefs urging this Court to affirm approval of the Penn-Central merger, citing the urgent need for this in order to salvage the New Haven’s operations. The attack, so far as the New Haven is involved, has been launched by Oscar Gruss & Son, a holder of approximately 14%' of the NH’s first and refunding mortgage bonds and by the Protective Committee for that issue, which intervened in Gruss’ action below. (Nos. 830 and 831.) The claim is that because continued operation of the New Haven at a loss involves progressive erosion of the bondholders’ security and [510]*510because the interim arrangement does not assure that Penn-Central will absorb all of the operating losses, we should not permit the Penn-Central merger to be consummated without simultaneous inclusion of the NH. In view of the probable difficulties in reaching agreement for inclusion of the NH which will satisfy its bondholders, it is virtually certain that this would mean lengthy delay during which the NH would not have access to the interim Penn-Central financial aid, and might be faced with collapse of its operations.
The Commission, after hearing the bondholders’ contention, pointed out that “[i]t is a fundamental aspect of our free enterprise economy that private persons assume the risks attached to their investments, and the NH creditors can expect no less because the NH’s properties are devoted to a public use. Indeed, the assistance the creditors are receiving from the States and would receive from Penn-Central through the sharing of operating losses would raise some of that burden from their shoulders.” Pennsylvania Railroad Company—Merger— New York Central Railroad Company, 331 I. C. C. 643, 704 (1967). The District Court, putting aside questions of the standing of the NH bondholders to attack the Penn-Central merger, affirmed the Commission’s rejection of the attack.
Continuation of the operations of the NH, which the Commission has found to be essential, can be assured only upon and after effectuation of the merger of the Penn-Central. The bondholders agree that to delay the Penn-Central merger until all proceedings necessary to include the NH have taken place may well mean the end of NH operations. The only realistic way to avoid this is to permit prompt consummation of the Penn-Central merger subject to appropriate conditions respecting the New Haven which Penn-Central will perforce accept by its act of merger. While the rights of [511]*511the bondholders are entitled to respect, they do not command Procrustean measures. They certainly do not dictate that rail operations vital to the Nation be jettisoned despite the availability of a feasible alternative. The public interest is not merely a pawn to be sacrificed for the strategic purposes or protection of a class of security holders whose interests may or may not be served by the destructive move.
While we reject the appeals of the NH bondholders, acceptance or rejection of the terms and conditions on behalf of the NH remains to be determined. The bondholders’ objections may be registered and adjudicated in the bankruptcy court or upon judicial review as provided by law. Furthermore, as noted above, the Commission has retained jurisdiction to make further appropriate orders, if necessary, and has provided both that inclusion of the NH in Penn-Central and the making of the loan arrangement on such terms as are prescribed by the Commission, are conditions of approval of the merger.
We affirm the District Court’s dismissal of the appeals in No. 830 and No. 831.
D. OBJECTIONS BASED ON THE PROVISIONS MADE POR THE PROTECTED ROADS.
The N & W and roads associated with its position (the Chesapeake & Ohio (C & 0), Baltimore & Ohio (B & O), and Western Maryland) have filed an appeal (No. 778). In brief and upon argument they stated that they do not object to the Penn-Central merger itself. Their stated position is that they oppose “immediate consummation”- — -that is prior to the actual inclusion of E-L, D & H, and B & M in the N & W. They also assail the specific operation and effect of the protective conditions and urge modifications thereof, and attack the basic legality of the conditions as a revenue pool.
The assailed protective provisions appear as Appendix G to the Commission’s order in the merger case. They [512]*512are essentially of two types: traffic conditions that require the merged Penn-Central not to change routes, rates, or service in such a way as to divert traffic from the protected lines; and revenue indemnity conditions establishing a formula whereby Penn-Central is to compensate the protected lines in the event of adverse revenue results following the merger.5 At the time the case was before us last Term, the Commission had withdrawn the revenue indemnity conditions pending further consideration. After our remand, the Commission further considered all the conditions, amended them in some respects not here material, and restored the revenue indemnity conditions. None of the protected roads has lodged objections against these provisions, nor has Penn-Central, and we affirm the District Court’s conclusion that they appear to provide adequate interim protection for the three roads in conformity with the purposes insisted upon by the Commission and which this Court sought to ensure by its decision last Term.6
[513]*513The objectors, however, attack the protective provisions on three grounds: First, they claim that the revenue indemnity provisions create a pooling agreement proscribed by § 5 (1) of the Interstate Commerce Act, 49 U. S. C. § 5 (1). Second, they say that the conditions give each of the protected lines an incentive to divert traffic to Penn-Central and vice versa. Such traffic diversion, they argue, would be at the expense of the objecting, “unprotected,” lines. Third, they also assert that the shield which these provisions give the protected lines dilutes their incentive to join the N & W, permits them or some of them unfairly to “shop around” for better terms of inclusion, and may delay or abort their inclusion in the N & W.
We first address ourselves to the argument assailing the indemnity provisions as an illegal pool. As the District Court pointed out, the legislative history of §5(1) leads to the conclusion that the section was not intended to apply to cases such as this one, in which the putative revenue pool is not the creation of private parties but is imposed by the Commission itself as a condition to consummation of a merger. Additionally, even if we consider the section applicable in these circumstances, there is no merit to the contention that the protective conditions must be struck down. Section 5 (1) proscribes “any contract, agreement, or combination [among] . . . carriers for the pooling or division of traffic, or of service, or of gross or net earnings, or of any portion thereof,” unless the Commission finds that such pooling or division “will be in the interest of better service to the public or of economy in operation, and will not unduly restrain corn-[514]*514petition.” The Commission has held that, even if the conditions it established were a pooling arrangement, “this record clearly supports findings . . . that to protect these carriers clearly is fin the interest of better service to the public’ ” and “ ‘will not unduly restrain competition.’ ” 330 I. C. C. 328, 345, n. 8. We agree with the District Court that this finding is supported by substantial evidence in the record. The interim protection of the protected lines is, in the Commission’s view and under the decision of this Court last Term, essential. These conditions have been adopted for that purpose and we see no reason on the present record to conclude that they are unlawful. In the event that actual experience reveals that the provisions operate inequitably, recourse may be had to the Commission for relief pursuant to its reserved jurisdiction, subject to judicial review.
With respect to the contention that, regardless of whether the indemnity provisions constitute a revenue pool, those provisions will induce the protected carriers and Penn-Central improperly to divert trafile to one another and thereby to injure the unprotected roads, the District Court correctly concluded that there is no basis for rejecting the Commission’s findings that neither the protected roads nor Penn-Central “would have either the motive or the ability to engage in such diversion on any substantial scale.” 279 F. Supp., at 328. This conclusion was reached largely because of the ability of the N & W to retaliate and the limitations imposed by economic conditions and geographic facts. The Commission included in its findings “a provision that would prohibit the protected carriers from engaging in manipulation, with sanctions if they do,” 330 I. C. C., at 355, and it specifically reserved jurisdiction to reopen proceedings and modify the protective conditions “in the light of experience.” The Commission has also included a gen[515]*515eral reservation of jurisdiction, under which it could revise the protective conditions.7 If, in light of experience, improper traffic diversions should develop or, as noted above, if these conditions should otherwise prove to be inequitable, recourse may be had to the Commission under these reservations, subject to judicial review as appropriate.8
N & W expresses the fear that the traffic and revenue indemnity provisions will be so attractive that the three lines or some of them will prefer to continue under their umbrella, and will not promptly accept the Commission’s ticket of admission to the N & W system. The Commission’s reserved power appears to be adequate to deter such conduct if and when it becomes abusive. Further, one of the protected lines, the largest of the three (E-L), already has accepted, by stockholder vote, its inclusion in N & W. The board of directors of [516]*516another (D & H) has recommended to stockholders that inclusion be accepted.9 In view of these circumstances, the fears expressed by N & W and the other protestants as to the dangers which perpetuation of these provisions will pose must be regarded as speculative. Clearly, if one or more of the protected roads should decline to accept the terms for inclusion specified by the Commission’s order, the Commission could be called upon to examine, pursuant to its reserved power, the appropriate action to be taken to terminate or modify the interim protective provisions or otherwise to ensure that the shield supplied to the roads is not converted into a sword. The fears expressed by the protestors fall far short of furnishing a reason for rejecting the District Court’s approval of the Commission’s order that the Penn-Central merger be immediately consummated. Nor is there merit to N & W’s contention that it was error for the Commission to fail to rule, now and forever, that the protected roads may not be included in Penn-Central. Whether or not such permission appears likely, there is no occasion for such contingent foreclosure.
Finally, we reject the contention that this Court’s prior opinion in this matter now precludes us from permitting consummation of the merger until actual inclusion of the three roads in a larger system. With respect to the inclusion problem, our criticism of the original Commission order ran to the ICC’s failure to decide the question over which it had undoubted jurisdiction and which [517]*517the Commission itself had found to be important to the public interest: the determination, so far as the Commission was empowered, of the ultimate home of the three roads. As this Court said: “we can only conclude that it is necessary that the [Commission’s] decision as to the future of the protected railroads and their inclusion in a major system be decided prior to consummation of the Penn-Central merger.” 386 U. S., at 390. Our decision was not intended to require an indeterminate delay in the consummation of the merger, pending the resolution of the jockeying, negotiating, and fighting among all of the parties concerned and completion of the multitudinous procedures necessarily involved. This would place the public interest as well as the vast majority of the affected private interests at the mercy of decisions not merely of certain corporations whose interests are, in fact, secondary or derivative, but of classes of security holders. It was our intention that the public interest should be served with fairness to all private parties concerned, not that it should be the captive of parties some of whom are understandably engaged in maneuvering solely for the purpose of improving their competitive, strategic, or negotiating positions.
There is no provision of law by which the Commission or the courts may compel the three protected roads to accept inclusion in the N & W, as ordered by the Commission, or in any other system: Section 5 (2)(d) of the Act provides:
“The Commission shall have authority in the case of a proposed transaction under this paragraph involving a railroad or railroads, as a prerequisite to its approval of the proposed transaction, to require, upon equitable terms, the inclusion of another railroad or other railroads in the territory involved, upon petition by such railroad or railroads request[518]*518ing such inclusion, and upon a finding that such inclusion is consistent with the public interest.”
It does not make provision for compelling an unwilling railroad which is not itself a party to a merger agreement to accept inclusion under the terms the Commission prescribes. Our opinion on the first appeals commanded the Commission to specify the opportunity provided for the smaller roads to be included in a major system, before approving consummation of the Penn-Central merger. It was not intended to give the protected corporations or the creditors or stockholders of each of them, or the N & W relying on their position, a veto over the public interest which the Commission has found to inhere in this merger.
We need not pause to discuss in detail N & W’s contention that the Commission’s findings do not support a conclusion that N & W must proceed with inclusion of fewer than all three of the protected roads, if, for example, B & M does not accept the terms. The original decision in the N & W-Nickel Plate merger proceedings clearly contemplates action by the Commission upon a “petition or petitions” of one or more of the three roads. 324 I. C. C. 1, 148. Separate petitions were in fact filed by each of these roads. As the District Court concluded, in light of the favorable action already taken by E-L stockholders and the D & H Board of Directors, the possibility of noninclusion of B & M would not be . cause for setting aside the Commission’s order.10
[519]*519E. THE POSITION OF BEADING CO.
No. 834 is an appeal on behalf of the Reading railroad. Reading does not ask that the consummation of the merger be stayed. Its complaint is directed to the District Court’s affirmance of the Commission’s refusal to permit Reading to reopen the record and submit evidence in support of its claim that it should receive protective conditions similar to those the three “protected roads” were given in Appendix G to the merger order.
Reading is controlled by the C & O-B & 0 system through stock ownership. It has been suggested under the so-called Dereco plan, that the proposed N & WC & O merger should include the Reading, as well as certain other small roads. Reading did not and does not ask for inclusion in Penn-Central, or for inclusion at this time in N & W along with E-L, D & H, and B & M. It did not offer evidence in the Penn-Central proceedings as to possible traffic diversion, until its tender made after the record had been closed. It now claims, however, that since much of its trackage is paralleled by lines of the Pennsylvania, it will be injured by the merger and should have the benefit of the Appendix G provisions.
Reading requests that we remand its case to the Commission for a decision as to whether protective conditions should be established for it. The Commission found, in its original report, that Reading would not be harmed [520]*520by the merger and that protective conditions were therefore unnecessary. This finding was based in part on a letter submitted by Reading itself to the Commonwealth of Pennsylvania and introduced, without objection from Reading, in evidence before the Commission. Only after the Commission issued its report did Reading object to the finding of no adverse impact upon it as a result of the merger, and then Reading’s fear appears to have been chiefly that a finding of no adverse impact might prejudice its eventual attempt to join in the N & W-C & 0 merger. The Commission held Reading to its “original concession that the effect of the merger transaction (without the indemnity conditions) upon them would be inconsequential.” 330 I. C. C. 328, 357. In response to Reading’s specific concern, the Commission modified its finding of no adverse impact to a finding that no adverse impact had been shown. The District Court upheld this decision and, in addition, concluded that Reading’s claim of substantial adverse impact as a result of the Penn-Central merger was unpersuasive on the merits.
Ordinarily, we would, without more, concur with the District Court’s view. Because of the vastness and complexity of this matter, however, and in order to ensure that whatever substance there may be to Reading’s claim is not sacrificed, we sustain the Commission’s denial of Reading’s submission on condition that it is without prejudice to any proceeding which Reading may hereafter institute, based on actual experience, for relief from undue prejudice caused by the merger.
II. Inclusion Decision.
Three appeals, No. 779, No. 833, and No. 836, relate to the Commission’s order, entered in the N & W-Nickel Plate merger proceedings, prescribing that N & W accept inclusion of the E-L, D & H, and B & M in the N & W system and specifying the terms thereof. Norfolk & [521]*521Western Railway Co. and New York, Chicago & St. Louis Railroad Co.—Merger, etc., 324 I. C. C. 1 (1964), supplemented, 330 I. C. C. 780, reconsidered, 331 I. C. C. 22 (1967). In 1964 the Commission approved the N & W-Nickel Plate merger subject, among other conditions, to the Commission’s retention of jurisdiction for five years to permit the filing of petitions by E-L, D & H, and B & M for inclusion in the N & W system. The Commission’s approval was also subject to the condition that N & W give its irrevocable consent to inclusion of the three roads on terms that the ICC would itself prescribe in the absence of agreement among the affected parties. 324 I. C. C. 1, 148. The three lines in due course filed petitions for inclusion. Hearings were held, and, on June 9, 1967, following our remand in the Penn-Central merger case, the Commission made findings and entered its order requiring N & W to include the three roads in its system under terms it prescribed.
Appellants are the N & W, the B & M, and a number of E-L bondholders. As we shall discuss, only the N & W appeal raises issues which go broadly to the merits of the Commission’s order implementing N & W’s duty to accept inclusion of the three roads. B & M seeks remand on the grounds that the terms fixed by the Commission for N & W’s offer to acquire the stock of the B & M are inadequate to reflect B & M’s value as part of the N & W system. The third appeal, brought by E-L bondholders, turns on the question whether the Commission should have specifically retained jurisdiction to protect the E-L bondholders in the event that N & W attempts after inclusion improperly to divert E-L traffic to itself. We affirm the District Court’s action in disallowing the claims of all of these appellants. Reference is made to preceding sections of this opinion for discussion of the bearing of claims respecting the inclusion order upon the Penn-Central proceeding.
[522]*522We first address ourselves to the demands of E-L bondholders for assurance that the reservation of jurisdiction by the Commission would enable them to obtain consideration of unwarranted traffic diversion by N & W, if that should develop. Since N & W will be acquiring stock control of E-L and E-L’s bondholders will look to E-L’s fortunes for payment and security, the bondholders fear that N & W may not be entirely solicitous of E-L’s welfare. Appellants themselves note that the Commission, in adopting the report and order of the officer presiding over the original hearing, has reserved jurisdiction “to receive such petitions, institute such investigations, and make such orders to accomplish the objectives and purposes of the plan for inclusion and other terms and conditions prescribed herein . . . .” The Commission has also retained jurisdiction “for the purpose of making such further order or orders in these proceedings as may be necessary or appropriate, in addition to those orders under jurisdiction expressly retained in the prior reports and orders of the Commission and to those orders which may be issued under section 5 (9) of the Interstate Commerce Act.” 11 Supplemental Order issued June 9, 1967. We have no doubt that if, after inclusion of E-L, N & W should engage in a course of conduct which invades the rights of E-L bondholders, the bondholders may apply to the Commission for relief and the Commission’s reservation of jurisdiction will enable it to rule upon this complaint and to grant relief, if warranted, subject to judicial review.
The other two appeals require somewhat more extended comment. We first note that our opinion at the [523]*523last Term found adequate support for the Commission’s conclusion that the public interest requires inclusion of the three roads in a larger system. As we have previously noted, see supra, at 503-505, the Commission’s findings and order with respect to the “public interest considerations” involved in the inclusion of these lines in the N & W system are in conformity with the statute and are supported by substantial evidence.
The attack of N & W and B & M upon the Commission’s order centers, not upon the fundamental issues, but upon the particular terms of that order. In brief, the Commission has provided that N & W will purchase stock control of E-L and B & M through wholly owned subsidiaries. It has fixed the basis for such purchase in relation to the experienced income of the lines, their earnings having been adjusted for various factors including savings and gains which the Commission found would result from inclusion in the N & W system. The Commission has satisfied itself that traffic losses to the merged Penn-Central would be offset by benefits to N & W not otherwise taken into account. The shareholders of these roads are to receive stock of a newly created subsidiary of N & W, which will eventually be convertible into N & W common stock. In the case of D & H, the means of valuation was the same as for the other protected lines, but N & W is to pay for D & H assets either in cash or with a note and N & W stock.
This is the first time in the Commission’s history that it has undertaken to “replace the bargaining session.” It did so here pursuant to the N & W stipulation, which was accepted by N & W as a condition to the N & W-Nickel Plate merger, and in response to the exigencies of the situation emphasized by this Court’s decision at our last Term.
As we have noted above, the E-L stockholders have voted approval of the inclusion terms. The D & H Board [524]*524of Directors has recommended approval to its stockholders. N & W complains that the price set for inclusion of the three lines is too high and that some other aspects of inclusion are arbitrary. B & M, on the other hand, complains that the price set for its inclusion is too low. The District Court affirmed the Commission’s findings and conclusions, and in the exercise of our reviewing function we find no basis for reversing that court’s decision.
The method for determining the value and exchange ratio which the Commission adopted, and which we have briefly described, is not attacked. It is a method that is reasonably conventional and generally accepted, always subject to the modifications and adaptations required by individual cases, and we see no basis for holding it erroneous as a matter of law. The attack that is launched is upon factors of particularized judgment and the weight to be ascribed to various values. These are matters as to which reasonable men may reasonably differ in detail, and we see no basis for setting aside the Commission’s conclusions as sustained by the District Court. In setting inclusion terms, the Commission was dealing with complicated and elusive predictions about probable traffic patterns following the Penn-Central merger and the inclusion decision. We are no more competent than the Commission and the District Court to ascertain the accuracy of those predictions. We deem it our function, in the complexities of cases such as these, to review the judgment of the District Court with respect td agency actions to make certain that those actions are based upon substantial evidence and to guard against the possibility of gross error or unfairness. If we find those conclusions to be equitable and rational, it is not for us to second-guess each step in the Commission’s process of deliberation.
[525]*525N & W’s attack upon the inclusion order centers upon its disagreement with the Commission’s findings as to prospective earnings of the three roads as part of the N & W system. It argues that the Commission had no basis for concluding that the earnings of E-L, D & H, and B & M, as subsidiaries of N & W, would be adequate to assure their “viability.”12 It asserts that the Commission has made various invalid adjustments of actual earnings and failed to make others. This, N & W says, is “the principal area of dispute in these proceedings.”
On the other hand, the B & M contends that the Commission’s findings substantially underestimate the savings which should be credited to it as an earnings adjustment, and that, therefore, the terms for its inclusion are unjust. Specifically, it urges that the Commission underestimated the probable amount of savings resulting from N & W control and the coordination of operations and equipment repair facilities and reduction of administrative expenses. The Commission, however, accepted and relied on figures submitted by B & M’s own witness. B & M now assails these figures, but obviously the Commission was entitled to rely upon them.
The District Court examined in some detail the contentions of the parties attacking the financial terms of the inclusion order. We have reviewed the findings of [526]*526the Commission in light of the evidence of record and the District Court’s analysis, and we find no basis for reversing the District Court’s judgment. The terms fixed by the Commission are clearly within the area of fairness and equity. Although B & M argues forcefully that the Commission underestimated the savings that should redound to its credit, we cannot say in the circumstances that the order should be reversed and remanded in this respect. It must be noted, as we have discussed in connection with appeals relating to the Penn-Central merger decision, that the inclusion order has no compulsive or coercive effect upon the roads to be included. Unless and until modified by the Commission, it remains available to the protected lines upon the terms which it specifies and which the District Court found to be fair and equitable.13
Only one other point of the N & W attack upon the inclusion order requires comment. N & W objects to the conditions prescribed by the Commission to protect the interests of the employees affected by the order. We note that those conditions, protecting employees of the protected lines, are the same as the conditions set by the Commission for N & W’s employees at the time of the N & W-Nickel Plate merger. As the District Court held, “[t]he Commission acted within its powers in requiring N & W to protect employees of the three roads as thoroughly as those of the roads it was permitted to absorb only on the condition that it would accept these lines if the Commission so directed.” 279 F. Supp., at 337.14
[527]*527III. Conclusion.
The judgment of the District Court for the Southern District of New York is affirmed, subject to the modifications and conditions stated in this opinion. Nos. 778, 779, 830-836 are remanded to that court for the entry of such orders and for such further action as may be consistent with our opinion and judgment herein and as may be appropriate with respect to the exercise of that court’s jurisdiction in the premises.
The applications of Scranton, Shapp, and Moosic for mandamus or certiorari (Nos. 663, Mise, and 664, Mise.) are denied without prejudice to further proceedings in the District Court for the Middle District of Pennsylvania, consistent with this opinion.
In No. 433, jurisdiction is noted, the judgment of the Middle District of Pennsylvania with respect to Potts-[528]*528ville is vacated, and the cause is remanded to that court for further proceedings in light of our decision today.
Mr. Justice Marshall took no part in the consideration or decision of these cases.