Full opinion text
MEMORANDUM DuBOIS, District Judge. TABLE OF CONTENTS I.BACKGROUND.695 A. THE STATUTORY EXEMPTION AND PUC’S COST-ASSESSMENT AUTHORITY.695 B. CASSATT AVENUE BRIDGE PROCEEDINGS.696 C. INITIAL SEPTA PROCEEDINGS.697 D. THE SEPTA CONSENT DECREE.698 E. PUC’S EFFORTS TO VACATE THE CONSENT DECREE .699 F. LLOYD STREET BRIDGE PROCEEDINGS.700 G. CURRENT PROCEEDINGS BEFORE THIS COURT .702 II.NORFOLK SOUTHERN’S MOTIONS TO INTERVENE.703 A. INTERVENTION AS OF RIGHT.703 B. PERMISSIVE INTERVENTION.705 III.SEPTA’S MOTION TO ENFORCE THE CONSENT DECREE .706 A. JURISDICTIONAL ISSUES: YOUNGER AND ROOKER-FELDMAN.706 B. CONFLICTING FEDERAL AND STATE COURT JUDGMENTS.707 1. Res Judicata and Enforcement of the Consent Decree.707 2. Analysis of PUC’s Counter Arguments.710 a. Waiver of res judicata defense.710 b. SEPTA’s permissible avoidance of state court litigation.711 c. Preservation of judgments under the All Writs Act.712 C. RELIEF — SEPTA.,.714 IV. PUC’S MOTIONS TO DISMISS AMTRAK’S COMPLAINT . lO i — l A. ELEVENTH AMENDMENT SOVEREIGN IMMUNITY. lO r — l B. EFFECT OF THE COMMONWEALTH COURT’S JUDGMENTS 10 i — I C. FAILURE TO JOIN NECESSARY PARTIES. i — I D. DECLARATORY JUDGMENT ACT REQUIREMENTS. QO t — I E. ABSTENTION. Oi rH F. INJUNCTIVE RELIEF AGAINST PUC COMMISSIONER AARON WILSON, JR. t — 1 OQ G. DISPOSITION OF PUC MOTIONS i — I C<J V. AMTRAK’S MOTIONS FOR DECLARATORY AND INJUNCTIVE RELIEF.721 A. LIKELIHOOD OF SUCCESS ON THE MERITS.723 B. IRREPARABLE HARM TO AMTRAK .725 C. HARM TO PUC.727 D. PUBLIC INTEREST.727 E. RELIEF — AMTRAK.728 VI. CONCLUSION.728 These related cases present important questions of federalism concerning state courts’ treatment of the final judgments of federal courts. Specifically, the cases raise the issue of how a litigant who has obtained a final federal judgment in its favor can enforce that judgment when a final order of a state court directly contradicts the earlier final federal order. The underlying issue is an oft-litigated question: whether PUC may allocate to SEPTA and Amtrak a share of the cost of maintaining and constructing highway bridges over railroad rights of way in the Commonwealth of Pennsylvania notwithstanding a federal statute exempting SEPTA and Amtrak from the payment of a “tax, fee, head charge, or other charge” imposed by a local taxing authority. In a series of decisions issued during the past fifteen years, judges of this Court have uniformly decided that federal statutory law exempts Amtrak and SEPTA from paying such costs. The Third Circuit has, in all instances, affirmed these decisions. Despite this long line of decisions, Pennsylvania state courts have issued opinions directly contradicting the federal courts’ rulings. The precise question now presented is whether Amtrak and SEPTA may continue to enforce the federal court judgments in their favor in the face of a state court’s conflicting interpretation of federal statutory law. As this Court now holds, the answer to that question is undeniably “yes.” In reaching this decision, the Court addresses seven pending motions. In the SEPTA case, No. 95^1500, there are two pending motions: Motion of SEPTA to Enforce the Consent Decree and Supporting Memorandum of Law (Doc. Nos. 20 and 21, filed Oct. 23, 2001); and Norfolk Southern’s Motion to Intervene as Interve-nor/Defendant (Doc. No. 24, filed Dec. 4, 2001). In the Amtrak case, No. 01-5570, there are five pending motions: Motion of the PUC to Dismiss the Verified Complaint in Equity filed by Amtrak (Doc. No. 6, filed Dec. 18, 2001); Motion of Commissioner Aaron Wilson, Jr., to Dismiss the Verified Complaint in Equity filed by Amtrak (Doc. No. 7, filed Dec. 18, 2001); Norfolk Southern’s Motion to Intervene as Interve-nor/Defendant and Supporting Memorandum of Law (Doc. Nos. 8 and 9, filed Dec. 21, 2001); Motion of Amtrak for Preliminary and Other Injunctive Relief (Doc. No. 12, filed Jan. 2, 2002); and Amtrak’s Renewed Motion for Declaratory Judgment and for Preliminary and Permanent Injunction (Doc. No. 22, filed May 8, 2002). For the reasons stated in this Memorandum, the Court will: (1) deny Norfolk Southern’s Motions to Intervene; (2) grant SEPTA’s Motion to Enforce the Consent Decree; (3) deny PUC’s Motions to Dismiss; and (4) grant Amtrak’s Motions for Declaratory and Injunctive Relief to the extent Amtrak seeks preliminary injunc-tive relief. I. BACKGROUND Since 1986, the parties now before the Court have litigated a number of cases, all of which have involved the allocation of costs for the maintenance and construction of highway bridges over railroad rights of way throughout Pennsylvania. Because the history of this litigation is essential to disposition of the pending motions, the Court now sets forth that history in some detail. A. THE STATUTORY EXEMPTION AND PUC’S COST-ASSESSMENT AUTHORITY In 1982, Congress enacted a statute aimed at protecting Amtrak, a federally owned and funded entity, from having to finance railway-related improvements which would otherwise be financed by state and local governments and other entities. That statute, as amended, provides, in relevant part: Amtrak, a rail carrier subsidiary of Amtrak, and any passenger or other customer of Amtrak or such subsidiary, are exempt from a tax, fee, head charge, or other charge, imposed or levied by a State, political subdivision, or local taxing authority on Amtrak, a rail carrier subsidiary of Amtrak, or on persons traveling in intercity rail passenger transportation or on mail or express transportation provided by Amtrak or such a subsidiary, or on the carriage of such persons, mail, or express, or on the sale of any such transportation, or on the gross receipts derived therefrom. 49 U.S.C. § 24301(i )(1) (“statutory exemption”). In 1988, Congress enacted further legislation extending the exemption to commuter authorities like SEPTA, providing that they are exempt “from paying a tax or fee to the same extent Amtrak is exempt.” 49 U.S.C. § 24301(f). Under this federal statutory scheme, both Amtrak and SEPTA are therefore “exempt from a tax, fee, head charge, or other charge, imposed or levied by a State, political subdivision, or local taxing authority.” 49 U.S.C. § 24301(0(1). In Pennsylvania, PUC is vested with the authority to assess costs for maintaining highway bridges, and, inter alia, to impose those costs on railroads. See Amtrak I, 665 F.Supp. at 403 (detailing PUC’s statutory authority to assess costs for maintaining highway bridges). In determining how it will assess costs — that is, to what entities it will allocate costs — PUC considers a number of factors, including the “benefit a party receives from a crossing.” Bell Atl.-Pa., Inc. v. Pa. Pub. Util. Comm’n, 672 A.2d 352, 355 (1995). PUC and Pennsylvania’s courts have recognized that railroads which own rights of way running underneath highway bridges derive a benefit from those bridges. See Pittsburgh & Lake Erie R.R. Co. v. Pa. Pub. Util. Comm’n, 124 Pa.Cmwlth. 611, 556 A.2d 944, 946 (1989). Those benefits include the avoidance of liability caused by accidents and concomitantly reduced insurance costs, as well as the elimination of any need to pay for and maintain crossing signals. Id. Because Amtrak and SEPTA both either own or use railroad rights of way throughout the Commonwealth of Pennsylvania, and thus benefit from highway bridges transversing those rights of way, PUC has, on several occasions during the past two decades, sought to impose costs for the maintenance of those bridges on Amtrak and SEPTA. Amtrak and SEPTA have argued, however, and judges of this Court have agreed, that the statutory provisions exempting them from paying a “tax, fee, head charge, or other charge, imposed or levied by a State, political subdivision, or local taxing authority” prevent PUC from allocating such costs to exempted entities like Amtrak and SEPTA. The Court will now summarize the proceedings in which this issue was addressed. B. CASSATT AVENUE BRIDGE PROCEEDINGS On May 30, 1986, PUC assessed to Amtrak costs involved in the replacement of a bridge in Tredyffrin Township carrying Cassatt Avenue over an Amtrak-owned right of way. Amtrak then brought suit in this Court, arguing that PUC’s assessment to Amtrak violated the statutory exemption. Although PUC agreed that Amtrak was exempt from taxes, it argued that the phrase “taxes” did not encompass the costs it had assessed to Amtrak. See Amtrak I, 665 F.Supp. at 408. Judge Newcomer rejected PUC’s argument in Amtrak I. Explaining that “[t]he common sense understanding of taxation to include any involuntary exaction to support a governmental entity or purpose is consistent with the intent of Congress expressed in the statute,” id. at 410, he concluded that the statute “exempts Amtrak from the payment of special assessments such as that imposed by PUC.” Id. at 412. Accordingly, Judge Newcomer permanently enjoined PUC from levying on Amtrak a tax “for design, construction or maintenance of the Cassatt Avenue bridge structures.” Id. PUC appealed Judge Newcomer’s decision to the Third Circuit, and that court affirmed in Amtrak II. In so doing, the Third Circuit defined the “precise issue” for consideration as “whether the phrase ‘any taxes or other fees’ contained in th[e] statute covers charges of the nature levied against Amtrak for building and maintaining the Cassatt Avenue bridge.” Amtrak II, 848 F.2d at 438. Substantially agreeing with Judge Newcomer’s analysis, the court explained that “[t]he statute’s text, its legislative history, and analogous case-law persuade us to give the exemption ... a broad interpretation that fulfills the intent of Congress.” Id. at 440. Because it would be “manifestly inconsistent” to compel Amtrak to “pay for related local improvements in the many instances where the states could, and would, impose them,” the court held “that Amtrak’s immunity from local ‘taxes or other fees’... extends to assessments for local improvements of the kind at issue here.” Id. C. INITIAL SEPTA PROCEEDINGS Notwithstanding the decisions in Amtrak I and Amtrak II, PUC continued to assess highway bridge maintenance costs to SEPTA. The Commonwealth Court affirmed these assessments in two decisions conflicting with the rulings in Amtrak I and Amtrak II. Concluding that PUC’s assessments of costs to SEPTA for maintenance of highway bridges did not constitute “taxes” as that term is used in the statutory exemption, the Commonwealth Court held the assessments permissible. SEPTA II, 592 A.2d at 810; SEPTA I, 592 A.2d at 803-04. In 1992, SEPTA brought an action in this Court, seeking a ruling that, like Amtrak, it was entitled to the protection of the statutory exemption. SEPTA sought this relief with respect to four bridges. SEPTA IV, 826 F.Supp. at 1511. Although PUC raised numerous arguments in opposition to SEPTA’s requested relief, the most relevant for present purposes involve PUC’s arguments aimed at distinguishing SEPTA’s case from the earlier Amtrak decisions — all of which Judge Pol-iak rejected in SEPTA TV. First, PUC argued that the language of the exemption statute did not extend Amtrak’s tax immunity to SEPTA. Judge Poliak rejected this argument and held that SEPTA was in fact covered by the statutory exemption. Id. at 1522-24. Second, PUC rehashed the argument asserted in the Amtrak cases that the costs imposed for highway bridge maintenance were not “taxes.” Again, Judge Poliak rejected this argument, finding no reason to distinguish the case from the Third Circuit’s decision in Amtrak II. Id. at 1524-26. See also SEPTA III, 802 F.Supp. at 1281 (Judge Poliak’s earlier decision examining in more detail and rejecting PUC’s arguments as to scope of “taxes” covered by statutory exemption). Upon finding the costs assessed to SEPTA undistinguishable from those ruled impermissible in Amtrak II, Judge Poliak ordered that “any assignment of costs to SEPTA by order of [PUC] for costs associated with design, construction, maintenance, inspection, or repair of’ the four bridges at issue would be in violation of the statutory exemption “as a tax or other fee levied upon SEPTA.” SEPTA IV, 826 F.Supp. at 1526. Additionally, Judge Pol-iak permanently enjoined PUC from “assessing such tax or other fee” regarding the four bridges, and from enforcing such assessment orders against SEPTA. Id. at 1526-27. The Third Circuit affirmed without opinion, and PUC’s petition for certio-rari was denied. Southeastern Pa. Transp. Auth. v. Pa. Pub. Util. Comm’n, 27 F.3d 558 (3d Cir.), cert. denied, 513 U.S. 928, 115 S.Ct. 318, 130 L.Ed.2d 279 (1994). D. THE SEPTA CONSENT DECREE Even after PUC exhausted its appeals of Judge Poliak’s decision, PUC continued to assess highway bridge maintenance costs to SEPTA. Given these continued assessments, in 1995, SEPTA filed a second action in this Court. That action is presently before the Court. In its Complaint, SEPTA sought much broader relief than that obtained before Judge Poliak, requesting an injunction preventing PUC from assessing against SEPTA “any costs associated with the design, construction, maintenance, inspection or repair” of one particular bridge, the Woodland Avenue bridge, “or any other bridges carrying highways over SEPTA commuter rail lines.” SEPTA Doc. No. 1 at 1 (emphasis added). In 1995, shortly after SEPTA filed its Complaint, the Commonwealth Court of Pennsylvania issued an opinion concerning highway bridge cost assessments and the statutory exemption. In contrast to its 1991 decisions discussed supra, § I.C., the Commonwealth Court’s 1995 opinion suggested that it had changed its position and concurred with the federal interpretation of the exemption. See Consolidated Rail Corp. v. Pa. Pub. Util. Comm’n, 671 A.2d 248, 250-51 (1995) (“Conrail ”) (citing and discussing with approval Amtrak II, 848 F.2d at 438); id. at 252 (“The PUC and this Court have duly recognized the federal preemption of the subject matter of state and local assessment of charges against Amtrak for repair or replacement of railroad crossings.”). It was in light of this decision, PUC now asserts, that it agreed to enter into a Consent Decree granting SEPTA substantially all of the relief sought in its Complaint. See SEPTA Doc. No. 22 at 3-4. The Consent Decree between SEPTA and PUC required PUC to rescind all previous costs allocated to SEPTA in violation of the statutory exemption and to reassign those costs to nonexempt parties. Consent Decree, SEPTA Doc. No. 10, filed Jan. 22, 1996 (“Consent Decree”), at ¶ 4. The Consent Decree also expressly precluded PUC from assessing any future costs in violation of the exemption: Unless permitted by subsequent amendment to, or repeal of [the statutory exemption], henceforth in all PUC above-grade crossing proceedings involving SEPTA railroad operations or SEPTA railroad rights-of-way, whether such proceedings are initiated by the Commission, SEPTA or by any other party, the Commission shall not assign to SEPTA, either on a temporary or on a permanent basis, any Assessed Cost or Responsibility in violation of SEPTA’s statutory exemption with respect to Highway Bridges as set forth in paragraph no. 1 of this Consent Decree. Id. at ¶3 (emphasis added). The parties agree that the costs at issue in this case are of the same nature as those defined in Paragraph No. 1 of the Consent Decree. One other provision of the Decree must be noted — the provision that the Court would “retain jurisdiction over this action to enforce the provisions of this Consent Decree, including any claims of SEPTA arising out of the Commission’s failure to comply with SEPTA’s federal statutory exemption.” Id. at ¶ 15. E. PUC’S EFFORTS TO VACATE THE CONSENT DECREE In 1996, less than three months after PUC entered into the Consent Decree with SEPTA, the Commonwealth Court issued a decision again disagreeing with the federal courts’ interpretation of the statutory exemption and holding that PUC could assess highway bridge costs to Amtrak. City of Philadelphia v. Pa. Pub. Util. Comm’n, 676 A.2d 1298, 1308-09 (1996) (“City of Philadelphia I ”). In 1998, the Commonwealth Court again addressed the applicability of the statutory exemption, specifically focusing on costs with respect to the Woodland Avenue bridge in Philadelphia. See City of Philadelphia v. Pa. Pub. Util. Comm’n, 720 A.2d 845 (1998) (“City of Philadelphia II”). The Woodland Avenue bridge had been the subject of the Commonwealth Court’s 1991 decision in SEPTA I, in which case the court approved PUC’s assessment of costs to SEPTA for maintenance on that bridge. In the 1998 case, however, PUC argued that this Court’s Consent Decree amounted to an “intervening change in the controlling law” which prevented PUC from assessing costs to SEPTA for the Woodland Avenue bridge. City of Philadelphia II, 720 A.2d at 848-49. The Commonwealth Court rejected PUC’s argument. Explaining that the 1991 decision was a final judgment with respect to the Woodland Avenue bridge, the court concluded that SEPTA could not collaterally attack that judgment in a federal court. Id. at 851 (citing Delaware Valley Citizens’ Council for Clean Air v. Pennsylvania, 755 F.2d 38, 43 (3d Cir.1985)). Accordingly, the Commonwealth Court held that PUC was required to assess to SEPTA costs for maintenance of the Woodland Avenue bridge consistent with the 1991 judgment. Id. at 852. In light of the Commonwealth Court’s decisions in City of Philadelphia I and City of Philadelphia II, PUC filed in this Comd a motion to vacate the Consent Decree. PUC raised three arguments in support of this motion: (1) this Court had no subject matter jurisdiction to approve the Consent Decree because the Full Faith and Credit Act, 28 U.S.C. § 1738, required the Court to defer to the Commonwealth Court’s 1991 decision; (2) the Court had no subject matter jurisdiction to approve the Consent Decree under the Rooker-Feldman doctrine; and (3) municipal and other governmental entities 'to which PUC assessed costs not assessed to SEPTA or Amtrak because of the statutory exemption were necessary parties to the action and impermissibly not joined. SEPTA V, 1999 WL 639946, at *3. This Court denied most of the relief requested in the PUC motion to vacate. With respect to PUC’s first argument concerning the Full Faith and Credit Act, this Court explained that PUC had never before raised a res judicata defense and had therefore waived that defense. Id. at *4-5 (citing Fed.R.Civ.P. 8(c)). In short, this Court held: “[SEPTA] brought this action in 1995. It is long past the time to raise an affirmative defense such as res judicata.” Id. at *5. Turning to PUC’s Rooker-Feldman argument, this Court acknowledged that the Commonwealth Court’s 1991 decision with respect to the Woodland Avenue bridge was a final judgment. Because that judgment was finalized before entry of the Consent Decree, “under Rooker-Feldman, the Court had no jurisdiction to approve the consent decree to the extent the decree affected SEPTA’s maintenance responsibilities with respect to the Woodland Avenue bridge.” Id. at *6. For that reason, this Court held that it must vacate the Consent Decree “insofar as it conflicts with the 1991 Commonwealth Court decision,” and it did so. Id. Finally, the Court rejected PUC’s argument that the Consent Decree should be vacated because necessary parties to the action were not joined. The Court explained: The third parties to which PUC refers, the various township and county governments in which the bridges at issue in this case lie, did not lose any legal rights under the consent decree. Rather, the Court, by approving the consent decree, declared that SEPTA was not responsible for the maintenance of the bridges. The adverse consequences of that order may have resulted in action by PUC which in turn affected the third parties, such as the shifting of maintenance costs to the third parties which might have been assumed by SEPTA absent the consent decree. However, the order itself had no such adverse effect. Id. at *7. For these reasons, the Court concluded that “the non party governmental entities were not necessary parties and deniefd] the PUC motion on that ground.” Id. The net effect of this Court’s 1999 decision, then, was to leave the Consent Decree intact except as it applied to the Woodland Avenue bridge. As to all other bridges incorporated in the Consent Decree, PUC was precluded from allocating to SEPTA “any Assessed Cost or Responsibility in violation of SEPTA’s statutory exemption.” Consent Decree at ¶ 3. F. LLOYD STREET BRIDGE PROCEEDINGS In 1997, before this Court’s decision rejecting PUC’s efforts to vacate the entire Consent Decree, PUC initiated proceedings to assess costs for maintenance and construction on the Lloyd Street Bridge in Chester, Pennsylvania. On September 1, 2000, PUC entered an order allocating these costs to governmental entities and private entities, including Consolidated Rail Corporation (“Conrail”). In light of the Third Circuit’s 1988 Amtrak II decision and this Court’s Consent Decree, PUC did not allocate any costs to either Amtrak or SEPTA. The parties to which PUC allocated costs appealed the 2000 PUC cost allocation order to the Commonwealth Court. That court, citing its 1996 decision in City of Philadelphia I, see supra § I.E., vacated PUC’s order. The court reasoned that “[b]ecause the PUC is a state administrative agency over which state courts have jurisdiction to determine what law it is to apply, including the interpretation of a federal law unless reversed by the United States Supreme Court, it was required to apply the holding in City of Philadelphia to this case.” City of Chester v. Pa. Pub. Util. Comm’n, 773 A.2d 1280, 1286 (Pa.Commw.Ct.2001) (“City of Chester I”). The court remanded the case to PUC “to conduct an additional hearing for the purpose of determining the allocation of costs associated with the Bridge that include Amtrak and SEPTA as well as all of the other parties involved.” Id. On remand, PUC issued an opinion and order dated September 7, 2001, revising its September 1, 2000, order. The revised order allocated to the City of Chester seventy-five percent of costs for maintenance and construction of the Lloyd Street bridge. The remaining costs were allocated to five separate parties, with each party assessed an equal share of five percent. The additional parties assessed five-percent of the costs included Amtrak and SEPTA, as well as Norfolk Southern, the successor in interest to Conrail. See PUC Sept. 7, 2001, Opinion and Order, SEPTA Doc. No. 20, Ex. E (“PUC Opinion and Order”) at 22. Since PUC issued its Opinion and Order, the parties to the actions now before the Court have submitted a number of filings in different fora. Because the Commonwealth Court had retained jurisdiction over the Lloyd Street bridge proceedings, see City of Chester I, 773 A.2d at 1288, that court required all parties to file exceptions to PUC’s order on remand by November 7, 2001. In the interim, PUC sought review before the Supreme Court of Pennsylvania, which review was denied. City of Chester v. Pa. Pub. Util. Comm’n, 567 Pa. 747, 788 A.2d 379 (2001). PUC then filed a petition for writ of certiorari in the United States Supreme Court, which petition was also denied. Pa. Pub. Util. Comm’n v. City of Chester, — U.S. -, 122 S.Ct. 1349, 152 L.Ed.2d 251 (2002). Norfolk Southern filed an appeal of the PUC Opinion and Order in the Commonwealth Court. As discussed below, see infra § I.G., on May 1, 2002, the Commonwealth Court decided that appeal in Norfolk Southern’s favor. Amtrak did not seek any relief in the Pennsylvania courts, but instead filed a motion before Judge Newcomer seeking to expand the Cassatt Avenue bridge injunction to cover all bridges crossing an Amtrak right of way. SEPTA, which also declined to seek relief in the Pennsylvania courts, moved to intervene in that action. On October 16, 2001, Judge Newcomer denied both motions, concluding that al-, though federal courts have determined that PUC may not assess costs to Amtrak for highway bridges, Amtrak had not demonstrated that PUC had violated the injunction with respect to the Cassatt Avenue bridge. See Complaint, Amtrak Doc. No. 1, Ex. F at 4. G. CURRENT PROCEEDINGS BEFORE THIS COURT On October 23, 2001, SEPTA filed its Motion to Enforce the Consent Decree. Thereafter, on November 2, 2001, Amtrak initiated a new action against PUC and its individual commissioners, and that action was assigned to this Court. Amtrak’s Complaint seeks relief in three counts: (1) a declaratory judgment that PUC has violated the statutory exemption; (2) a preliminary and permanent injunction barring PUC from imposing costs on Amtrak with respect to any highway bridge in Pennsylvania; and (3) enforcement of prior judgments with respect to the applicability of the statutory exemption on collateral es-toppel grounds. PUC and the individual commissioners then filed two separate Motions to Dismiss Amtrak’s Complaint. Additionally, on January 2, 2002, Amtrak filed a Motion for Preliminary and Other In-junctive Relief. Amtrak’s Complaint and request for injunctive relief seek substantially the same relief as the Court granted SEPTA in approving the Consent Decree in 1996. Norfolk Southern, which was also assessed costs by PUC in the Lloyd Street Bridge proceedings, moved under Fed. R.Civ.P. 24 to intervene as a defendant in both the SEPTA and Amtrak cases. Norfolk Southern argues in both motions that it has a significant interest in the outcome of this litigation because its responsibility for bridge maintenance costs is directly affected by whether costs are assessed to Amtrak and SEPTA. Both Amtrak and SEPTA oppose Norfolk Southern’s motions to intervene. PUC does not oppose these motions. Upon receiving and reviewing the first of these filings, the Court convened a telephone status conference on December 20, 2001. After discussion with the parties about the issues presented by the pending motions, the Court ordered, on December 20, 2001, submission of supplemental briefing on the “issues presented by the conflict, or potential conflict, between the state court which has ruled on the issues, the Commonwealth Court, and the Federal Consent Decree and/or other Federal Orders issued or sought by the parties.” The Court also scheduled an oral argument on all pending motions. The parties submitted all filings in accordance with the December 20, 2001, Order. The Court held oral argument on January 11, 2002. After oral argument, the Commonwealth Court, on May 1, 2002, decided Norfolk Southern’s appeal of PUC’s September 7, 2001, Opinion and Order assessing costs with respect to the Lloyd Street bridge. See City of Chester v. Pa. Pub. Util. Comm’n, 798 A.2d 288 (2002) (“City of Chester II ”). In that decision, the Commonwealth Court agreed with Norfolk Southern’s objection to the Opinion and Order “that the Commission does not have jurisdiction to allocate maintenance costs to [Norfolk Southern] because only the owner of property and facilities at a rail crossing is liable for maintenance obligations.” Id. at 292. Following this conclusion, the court held that “because an owner of a railroad with a crossing over its line is the party responsible for costs associated with that rail line, and there is no dispute that Amtrak, not Norfolk Southern, is the owner of the rail-line and crossing at issue,” PUC’s assessment of costs to Norfolk Southern was an abuse of discretion. Id. at 294. In light of that abuse of discretion, the court ordered that the five-percent assessment of costs allocated to Norfolk Southern be shifted to Amtrak, thus resulting in a judgment assessing to Amtrak ten percent of the costs for maintenance on the Lloyd Street bridge. Id. at 294-95. In response to the Commonwealth Court’s decision, Amtrak filed its Renewed Motion for Declaratory Judgment and for Preliminary and Permanent Injunction. Amtrak’s Renewed Motion broadens the scope of requested relief by seeking, in addition to the injunctive relief initially sought, a declaratory judgment that the Commonwealth Court’s City of Chester II decision is “null and void” insofar as it applies to Amtrak. The Court will next proceed to consider each motion, or set of related motions, in turn. II. NORFOLK SOUTHERN’S MOTIONS TO INTERVENE Norfolk Southern seeks to intervene as a defendant in both the SEPTA case and the Amtrak case. Norfolk Southern is not a covered entity under the statutory exemption and requests intervention on the ground that highway bridge costs not assessed to Amtrak or SEPTA pursuant to the federal court interpretation of the exemption might be assessed to it. Should the Court permit intervention in the SEPTA case, Norfolk Southern asserts that it will move to vacate the consent decree. In the Amtrak case, Norfolk Southern states it will seek to relitigate the Third Circuit’s determination in Amtrak II as to the scope of the exemption. In both cases, Norfolk Southern says it will ask the Court to address the proper assessment of costs. In the motions to intervene, Norfolk Southern argues that it is entitled to intervene as of right under Fed.R.Civ.P. 24(a)(2), or, alternatively, that it should be permitted to intervene under Fed.R.Civ.P. 24(b)(2). Because the motions in both cases are substantially the same, and because SEPTA’s and Amtrak’s responses to both of the motions are, likewise, substantially the same, the Court will address the motions together. For the reasons set forth below, the Court concludes that Norfolk Southern has failed to meet the threshold requirements for both forms of intervention under Fed.R.Civ.P. 24. A. INTERVENTION AS OF RIGHT An applicant for intervention may intervene as of right when: (1) “the applicant claims an interest relating to the property or transaction which is the subject of the action”; (2) “the applicant is so situated that the disposition of the action may as a practical matter impair or impede the applicant’s ability to protect that interest”; and (3) the applicant’s interest is not “adequately represented by existing parties.” Fed.R.Civ.P. 24(a)(2). The application for intervention must also be timely. Harris v. Pernsley, 820 F.2d 592, 596 (3d Cir.1987). To meet the first of the above requirements, Norfolk Southern’s “interest must be one that is ‘significantly protectable.’ ” Mountain Top Condo. Ass’n v. Dave Stabbert Master Builder, Inc., 72 F.3d 361, 366 (3d Cir.1995) (quoting Donaldson v. United States, 400 U.S. 517, 531, 91 S.Ct. 534, 27 L.Ed.2d 580 (1971)). In explaining what makes an interest “significantly protectable,” the Third Circuit has “held that, ‘the interest must be a legal interest as distinguished from interests of a general and indefinite character.’ ” Id. (quoting Harris, 820 F.2d at 601) (internal citations omitted). Importantly, “a mere economic interest in the outcome of the litigation is insufficient to support a motion to intervene.” Id. (citing United States v. Alcan Aluminum, Inc., 25 F.3d 1174, 1185 (3d Cir.1994); New Orleans Public Serv., Inc. v. United Gas Pipe Line Co., 732 F.2d 452, 464 (5th Cir.1984) (“NOPSI”)); see also Coram Healthcare Corp. v. Aetna U.S. Healthcare, Inc., 1999 WL 1017403, at *1 (E.D.Pa. Nov. 3, 1999). Upon a review of the parties’ filings and upon hearing counsel for Norfolk Southern’s arguments at oral argument, the Court concludes that Norfolk Southern’s claimed interest in these proceedings can only be described as a “mere economic” one. In short, Norfolk Southern is seeking to intervene solely on the ground that the Court’s enforcement of the SEPTA Consent Decree, and, likewise, the Court’s issuance of injunctive relief in the Amtrak case, would compel Norfolk Southern to pay larger assessments. This claimed interest is not sufficient to justify intervention as of right under Fed.R.Civ.P. 24(a)(2). Examination of two cases with similar claimed interests lends further support to the Court’s conclusion. The first case is the Fifth Circuit’s decision in NOPSI, which involved a contract between an investor-owned utility and a supplier of natural gas. NOPSI, 732 F.2d at 455. The utility sued the supplier for declaratory relief concerning interpretation of certain terms of the contract. Id. at 459-60. Customers of the utility subsequently moved to intervene asserting that they had an interest in the case because the litigation might result in higher rates. Id. at 460-62. Finding that the “the only ‘interest’ asserted as a basis for intervention [was] a purely economic interest,” the court held this interest insufficient for intervention under Fed.R.Civ.P. 24(a)(2). Id. at 466. A second analogous, and more recent, case is the Eighth Circuit’s decision in Curry v. Regents of Univ. of Minn., 167 F.3d 420 (8th Cir.1999). In that case, five students brought suit against the defendants alleging that the University of Minnesota’s Student Services Fee violated their constitutional rights to the extent their fees were distributed to campus student groups whose purposes the plaintiff students found objectionable. Id. at 421. The plaintiffs’ complaint specifically named three student groups. Id. The three named student groups then moved to intervene, arguing that the lawsuit threatened their right to disbursement of the Student Services Fee. Id. The court rejected the motions to intervene, finding that the applicants had not established a sufficient interest in the subject matter of the lawsuit. Id. at 422. The mere assertion of an economic interest, “maintaining the quantum of their funding,” did not, the court concluded, “rise to the level of a legally protectable interest necessary for mandatory intervention.” Id. at 422-23 (citing Standard Heating and Air Conditioning Co. v. City of Minneapolis, 137 F.3d 567, 571 (8th Cir.1998); Greene v. United States, 996 F.2d 973, 976 (9th Cir.1993)). Norfolk Southern’s claimed interest is directly analogous to the interests claimed in NOPSI and Curry. Just like utility customers concerned about the implications of their utility’s supply contract, and just like student groups’ concerns about the continued distribution of a student services fee, Norfolk Southern’s interest is limited to the economic effects generated by the outcome of this litigation. The impropriety of allowing Norfolk Southern to intervene as of right in these cases is further demonstrated by counsel for Norfolk Southern’s own admission at oral argument. Asked whether, in line with the economic interest claimed by Norfolk Southern to establish a protectable interest under Fed.R.Civ.P. 24(a)(2), the Court should allow any party which might be ordered to pay highway bridge assessments in lieu of SEPTA or Amtrak to intervene as of right, Norfolk Southern’s counsel answered in the affirmative. See Jan. 11, 2002, Hr’g Tr. at 87-88. Counsel agreed that, given the nature of these cases, this view would require intervention by every state and local governmental entity or private party that might benefit from a highway bridge — resulting in an untold (but certainly large) number of parties. This result — intervention by a large number of parties with economic interests only — is certainly not one countenanced by the precedents discussed above. Thus, like the Fifth and Eighth Circuits, and in accordance with the principles set forth by the Third Circuit in Mountain Top, the Court concludes that Norfolk Southern may not intervene as of right in these cases. B. PERMISSIVE INTERVENTION Any party may be permitted to intervene in an action when “an applicant’s claim or defense and the main action have a question of law or fact in common.” Fed.R.Civ.P. 24(b)(2). Intervention under this rule is a matter left to this Court’s discretion. See, e.g., Hoots v. Pennsylvania, 672 F.2d 1133, 1135-36 (3d Cir.1982). Norfolk Southern asserts that it wants to litigate a question of law common to both the SEPTA and Amtrak cases— the applicability and scope of the statutory exemption. More specifically, Norfolk Southern seeks to intervene in this case to vacate the SEPTA-PUC consent decree and relitigate the issue adjudicated by the Third Circuit in the Amtrak-PUC litigation. In short, Norfolk Southern seeks to have the Court consider the merits. That issue, however, is not at all the focus of these proceedings. Rather, these proceedings involve procedural issues — the enforceability of prior federal court judgments in the face of conflicting state court judgments. In light of the focus of these proceedings, the Court concludes that the issues Norfolk Southern seeks to litigate are not at all “common” to the “main action.” Fed.R.Civ.P. 24(b)(2). Moreover, to the extent that Norfolk Southern seeks to add to PUC’s response to the res judicata and collateral estoppel arguments asserted by SEPTA and Amtrak, the Court concludes that Norfolk Southern’s defenses are du-plicative of those raised by PUC. Thus, Norfolk Southern’s intended responses are an insufficient basis for permissive intervention. See Brock v. McGee Bros. Co., 111 F.R.D. 484, 487 (W.D.N.C.1986) (“It is doubtful ... whether [Fed.R.Civ.P. 24(b)(2) ] was intended to provide for intervention by an applicant who apparently desires merely to assist in asserting the same defense already asserted by the Defendant.”). There is no basis for permitting Norfolk Southern to intervene in this case. Therefore, the Court will not allow permissive intervention. III. SEPTA’S MOTION TO ENFORCE THE CONSENT DECREE SEPTA argues as follows in support of its motion: The Consent Decree approved by this Court prohibited PUC from allocating “any Assessed Cost or Responsibility in violation of SEPTA’s statutory exemption.” Consent Decree at ¶ 3. PUC has assigned costs to SEPTA for maintenance and construction of the Lloyd Street bridge. SEPTA is exempted from such costs under the statutory exemption and PUC’s assessment thus violates the Consent Decree. Because the Court retained jurisdiction to enforce the Consent Decree, see Consent Decree at ¶ 15, the Court should enjoin PUC from assessing to SEPTA costs with respect to the Lloyd Street bridge. PUC makes a number of arguments in response to SEPTA’s motion, which, in summary, assert that: (1) this Court should not exercise jurisdiction in this matter under either the Younger abstention doctrine, see Younger v. Harris, 401 U.S. 37, 91 S.Ct. 746, 27 L.Ed.2d 669 (1971), or the Rooker-Feldman doctrine, see District of Columbia Court of Appeals v. Feldman, 460 U.S. 462, 103 S.Ct. 1303, 75 L.Ed.2d 206 (1983); Rooker v. Fidelity Trust Co., 263 U.S. 413, 44 S.Ct. 149, 68 L.Ed. 362 (1923); and (2) the Court should not enforce the Consent Decree because such a disposition would subject PUC to conflicting orders from a state court and a federal court. The Court will address each of PUC’s arguments in turn. A. JURISDICTIONAL ISSUES: YOUNGER AND ROOKER-FELDMAN ' PUC’s arguments that the Court should not exercise jurisdiction over this matter can be disposed of summarily. The Younger doctrine generally dictates federal court abstention in cases involving ongoing state-court proceedings. That doctrine is inapplicable, however, in cases where “proceedings of substance on the merits have taken place in the federal court.” Hawaii Hous. Auth. v. Midkiff 467 U.S. 229, 238, 104 S.Ct. 2321, 81 L.Ed.2d 186 (1984) (internal quotations and citations omitted); see also Ford Motor Co. v. Ins. Comm’r of Commonwealth of Pa., 874 F.2d 926, 932 n. 8 (3d Cir.1989). SEPTA’s case against PUC has been before this Court since 1995. The proceedings resulted in a Consent Decree, “an agreement that the parties desire and expect will be reflected in, and be enforceable as, a judicial decree that is subject to the rules generally applicable to other judgments and decrees.” Rufo v. Inmates of Suffolk County Jail, 502 U.S. 367, 378, 112 S.Ct. 748, 116 L.Ed.2d 867 (1992); see also United States v. Athlone Indus., 746 F.2d 977, 983 n. 5 (3d Cir.1984) (citing Interdynamics, Inc. v. Firma Wolf, 653 F.2d 93, 96-97 (3d Cir.1981)) (“A consent decree is generally treated as a final judgment on the merits and accorded res judicata effect.”). But see Imprisoned Citizens Union v. Shapp, 11 F.Supp.2d 586, 596-98 (E.D.Pa.1998), aff'd, 169 F.3d 178 (3d Cir.1999) (holding that consent decree is not a “final judgment” for separation-of-powers purposes such that Congress could permissibly change law governing prospective relief provided in consent decree). The state proceedings with respect to the Lloyd Street bridge began, at the absolute earliest, in 1997, when PUC commenced its investigation into maintenance of that bridge. The Consent Decree, which is a final judgment on the merits, and can therefore only be the result of “proceedings of substance on the merits” in a federal court, was approved in 1996. Younger abstention is therefore inapplicable in this case. A similar analysis as to timing — that is, that the federal Consent Decree was finalized before initiation of the state proceedings — applies in the Rooker-Feldman context. That doctrine prevents a federal court from exercising jurisdiction “when in order to grant the federal plaintiff the relief sought, the federal court must determine that [a] state court judgment was erroneously entered or must take action that would render that judgment ineffectual.” FOCUS v. Allegheny County Court of Common Pleas, 75 F.3d 834, 840 (3d Cir.1996). The doctrine is inapplicable, however, when, as in this case, the federal litigation begins before the state court litigation. Central Reserve Life Ins. Co. v. Marello, 2001 WL 41129, at *4 (E.D.Pa. Jan. 17, 2001) (citing Doctor’s Assocs. v. Distajo, 107 F.3d 126, 138 (2d Cir.1997)). The Court therefore finds that the Rooker-Feldman doctrine does not bar its exercise of jurisdiction over SEPTA’s motion. B. CONFLICTING FEDERAL AND STATE COURT JUDGMENTS The Court acknowledges that enforcement of the Consent Decree will, as PUC laments, subject PUC to two inconsistent judgments. On the one hand, this Court’s Order prohibits PUC from assessing to SEPTA highway bridge maintenance costs, while, on the other hand, the Commonwealth Court’s order requires PUC to do exactly that. The Court notes that PUC has not exhibited any ill motive or other contemptuous behavior in violating this Court’s Consent Decree. When PUC entered into the Consent Decree, it believed, based on the Commonwealth Court’s 1995 decision in Conrail, that the Commonwealth Court and federal courts were in agreement in interpreting the scope of the statutory exemption. See Conrail, 671 A.2d at 250-52. Nevertheless, the potential for conflict and lack of ill motive are not valid reasons for this Court to stay its hand in enforcing the Consent Decree. On the contrary, the potential for conflict gives the Court all the more reason to enforce the Consent Decree under the authority of Delaware Valley Citizens’ Council for Clean Air v. Pennsylvania, 755 F.2d 38 (3d Cir.1985) (“Delaware Valley ”), a case quite analogous to the present one. In this section, the Court will first discuss how principles of res judicata, as explained in Delaware Valley, compel the Court’s enforcement of the Decree. The Court will then address several of PUC’s counter arguments to such enforcement. 1. Res Judicata and Enforcement of the Consent Decree In the Third Circuit’s Delaware Valley decision, the plaintiffs sought an injunction compelling the Commonwealth of Pennsylvania to implement a vehicle emission and maintenance program as required by federal regulations. Delaware Valley, 755 F.2d at 40. The parties entered into a Consent Decree under which the Commonwealth defendants were obligated to seek legislation establishing and implementing such a program. Id. Unhappy with the mandates of the Consent Decree, several Pennsylvania state legislators filed state court actions for declaratory judgments decreeing that the Commonwealth parties who had entered into the Consent Decree lacked the legal authority to do so. Id. These lawsuits resulted in the Supreme Court of Pennsylvania’s ruling that the Commonwealth officials had no authority to enter into the Consent Decree; on remand, the Commonwealth Court enjoined state officials from complying with the Decree. Id. at 41 (citing Scanlon v. Commonwealth, 502 Pa. 577, 467 A.2d 1108, 1115 (1983)). The Commonwealth then returned to the district court overseeing the Consent Decree seeking to vacate the Decree. Id. The- district court denied the Commonwealth’s request. Id. On the Commonwealth’s appeal, the Third Circuit explained that the merits of the state court’s decision were irrelevant because “resolution of this particular dispute turns on the efficacy of final judgments rendered by the federal court system.” Id. The state court’s declaration that the Consent Decree was a nullity, the Third Circuit stated, “flies in the face of settled law and the doctrine of res judicata.” Id. at 42. Specifically, the Supreme Court of Pennsylvania’s decision violated the provisions of 28 U.S.C. § 1738, the full faith and credit statute. Although the language of that statute, which implements the Constitution’s full faith and credit clause of Article IV, § 1, refers only to state court judgments, “there ‘is a clearly established rule that state courts must give full faith and credit to the proceedings of federal courts.’ ” Id. at 43 (quoting Degnan, Federalized Res Judicata, 85 Yale L.J. 741, 744 (1976)). The governing rule, then, as stated by the United States Supreme Court, provides: “ ‘[WJhere the judgment or decree of the federal court determines a right under a federal statute, that decision is final until reversed in an appellate court, or modified or set aside in the court of its rendition.’ ” Id. at 44 (quoting Stoll v. Gottlieb, 305 U.S. 165, 170, 59 S.Ct. 134, 83 L.Ed. 104 (1938)) (emphasis supplied) (further internal quotations and citations omitted). In light of this principle, the Commonwealth was “bound by the federal judgment under res judicata,” and the merits of the Supreme Court of Pennsylvania’s decision were “irrelevant to the overarching question of the competency of a state court to interfere with a final, federal court judgment bottomed on federal law.” Id. Accordingly, the Third Circuit affirmed the district court’s denial of the Commonwealth’s motion to vacate the Consent Decree. Id. at 45. The rule of Delaware Valley is clearly applicable to this case. The Consent Decree entered into by SEPTA and PUC is a federal court decree determining the parties’ rights under a federal statute. That Decree is therefore final until reversed by the Third Circuit or until this Court modifies or sets aside the Decree. The Commonwealth Court was bound by the Decree and should have enforced it in the Lloyd Street bridge proceedings. The reasons advanced by the Commonwealth Court in City of Chester I for allowing PUC to assess fees to Amtrak and SEPTA are irrelevant to this Court’s determination. Notwithstanding these clear legal rules, the Commonwealth Court has stated that it is not bound by this Court’s Consent Decree. See City of Philadelphia I, 676 A.2d at 1307 n. 16 (“Of course, we are not bound by the consent decree.”); see also City of Chester I, 773 A.2d at 1285 (reaffirming finding in City of Philadelphia I that Commonwealth Court was not bound by the Decree). These statements are legally incorrect. The Commonwealth Court’s conclusion was based on its concern that the Consent Decree “deprived the parties that were not a party to that decree of their due process rights to a full and fair hearing.” City of Chester I, 773 A.2d at 1285. Regardless of this concern, the Commonwealth Court was not relieved of its duty to give full faith and credit to this Court’s final judgment embodied in the Consent Decree. The Commonwealth Court’s failure to do so disregards numerous Pennsylvania decisions acknowledging the principles set forth by the Third Circuit in Delaware Valley. In that case, the Third Circuit stated that “Pennsylvania courts have long recognized the principle that state courts are bound by the judgments of federal courts.” Delaware Valley, 755 F.2d at 44 (citing London v. City of Philadelphia, 412 Pa. 496, 194 A.2d 901, 902-03 (1963); Bardo v. Commonwealth, 40 Pa.Cmwlth. 585, 397 A.2d 1305, 1307 n. 1 (1979)). Significantly, the Commonwealth Court has also recognized these principles — in some cases. As discussed earlier, the Commonwealth Court had approved the allocation to SEPTA of costs for the Woodland Avenue bridge in its 1991 SEPTA I decision. See supra § I.C. After PUC entered into the Consent Decree before this Court, it reallocated SEPTA’s costs to the City of Philadelphia. City of Philadelphia II, 720 A.2d at 848. The City then sought review of PUC’s allocation. Before the Commonwealth Court, PUC argued that the City could not challenge the impact of the Consent Decree. Id. at 849. The Commonwealth Court correctly identified the flaws in PUC’s argument, explaining that the City was not challenging the Consent Decree, but seeking to “have [the court’s] prior order imposing maintenance obligations on SEPTA given preclusive effect as required by the Full Faith and Credit Act.” Id. at 850. By way of further explanation, the court pointed to Delaware Valley, calling it “[particularly apropos to the facts of this case,” id., as follows: While Delaware Valley involved a later state decision that affected an earlier consent decree rather than, as here, a latter federal consent decree that affects an earlier state court judgment, we make the same observation: Unsuccessful before the PUC and this Court and rebuffed by our Supreme Court, SEPTA attempted a collateral attack on the several final judgments of the Public Utility Commission and the courts of this Commonwealth that was acceded to by the PUC. Id. at 851. The court therefore rejected PUC’s argument and ordered it to reinstate its allocation orders as to the Woodland Avenue bridge approved in 1991. Id. at 852. It was in light of the Commonwealth Court’s correct analysis in City of Philadelphia II that this Court issued its 1999 decision vacating the Consent Decree to the extent that it prevented PUC from allocating costs to SEPTA with respect to the Woodland Avenue bridge. See SEPTA V, 1999 WL 639946, at *6. The Commonwealth Court’s order allowing assessments to SEPTA with respect to that bridge was a final judgment that this Court could not reverse. See supra § I.E. (discussing va-catur of Consent Decree as to Woodland Avenue bridge on Rooker-Feldman grounds). After that 1999 decision, the remainder of the Decree, which applied to all other highway bridges, remained intact. Accordingly, absent any meritorious arguments as to why the Decree did not remain enforceable, the Commonwealth Court should have given effect to the Decree. 2. Analysis of PUC’s Counter Arguments PUC raises a number of arguments urging the Court to refuse enforcement of the Decree. The Court addresses three of those arguments regarding (1) deference to the Commonwealth Court’s rulings; (2) SEPTA’s opportunity to defend its exemption in state court; and (3) the purported impracticalities of conflicting federal and state court judgments. The Court rejects each of these arguments because (1) PUC has waived a res judicata defense; (2) SEPTA has permissibly — and strategically — -not appeared in state court to defend its exemption so as to prevent an adverse res judicata ruling under Parsons Steel, Inc. v. First Alabama Bank, 474 U.S. 518, 106 S.Ct. 768, 88 L.Ed.2d 877 (1986); and (3) the Court will be able to enforce its judgment under the All Writs Act. The Court now briefly discusses the reasoning supporting these conclusions. a. Waiver of res judicata defense PUC argues that this Court should defer to the Commonwealth Court’s decisions holding the statutory exemption inapplicable to PUC cost assessments. This is the same argument PUC made in 1999 when asking the Court to vacate the Consent Decree. Before that 1999 motion to vacate the Consent Decree, however, PUC had not raised a res judicata defense. Accordingly, this Court held that PUC had waived that defense. See SEPTA V, 1999 WL 639946, at *4-5 (citing, inter alia, Fed.R.Civ.P. 8(c)). That ruling is the law of this case. See In re Continental Airlines, Inc., 279 F.3d 226, 232-33 (3d Cir.2002) (stating that law of the case doctrine “is concerned with the extent to which the law applied in decisions at various stages of the same litigation becomes the governing legal precept in later stages” and that doctrine “limits relitigation of an issue once it has been decided”). If PUC wanted to argue the res judicata defense — that this Court should defer to the Commonwealth Court’s decisions — it should have raised that defense before it decided to enter into the Consent Decree; PUC may not reargue its previously rejected res ju-dicata defense to escape the effect of that Decree. Cf. Delaware Valley, 755 F.2d at 44 (noting that Commonwealth defendants should have litigated merits of their claim before entering into the Consent Decree). b. SEPTA’s permissible avoidance of state court litigation PUC argues that SEPTA should be held responsible for failing to defend its exemption in state court proceedings by appearing as a party. As an initial matter, SEPTA is under no legal duty to appear in state court to preserve a federal judgment in its favor. More importantly, SEPTA has chosen not to appear in state court actions for good reasons. At oral argument, SEPTA asserted that should it enter litigation before the Commonwealth Court in defense of its exemption, that court could explicitly refuse to give full faith and credit to the federal courts’ judgments. This Court, argues SEPTA, would then be bound to give the Commonwealth Court’s judgment res judicata effect against SEPTA — that is the Commonwealth Court’s judgment as to res judicata would be entitled to res judicata effect in this Court. Such is the situation that arose in Parsons Steel, Inc. v. First Alabama Bank, 474 U.S. 518, 106 S.Ct. 768, 88 L.Ed.2d 877 (1986). In that case, the plaintiff sued the defendant bank in two separate actions, one in state court and one in federal court. Id. at 520, 106 S.Ct. 768. The federal court entered judgment in favor of the defendant, and the defendant subsequently pleaded defenses of res judicata and collateral estoppel in the state court. Id. The state court, however, rejected these defenses, and the state court litigation resulted in a jury verdict of four million dollars against the defendant. Id. The defendant sought an injunction from the federal court to prevent execution of the state court judgment and to enforce the federal court judgment in its favor; that relief was granted. Id. at 520-21, 106 S.Ct. 768. The Supreme Court then held that the district court could not grant the injunction without first considering the preclu-sive effect of the state-court’s judgment rejecting the defendant’s res judicata and collateral estoppel defenses. Id. at 525, 106 S.Ct. 768. As one commentator has explained, the effect of Parsons Steel is to require that “once the res judicata issue was raised in state court and decided, then the federal court must accept the state’s determination that there is not preclusion.” Erwin Chemerinsky, Federal Jurisdiction § 11.2.4 (2d ed.1994). After the state court proceedings were completed in Parsons Steel “and especially once the res judicata issue was ruled on by the state court, then the federal court was bound by the state court’s determination.” Id. See also Del. River Port Auth. v. Fraternal Order of Police, 290 F.3d 567, 573 n. 8 (3d Cir.2002) (citing Parsons Steel, 474 U.S. at 525, 106 S.Ct. 768) (“Even ... where the state court — arguably wrongly — did not find any preclusive effect, the Supreme Court unanimously refused to allow the prior federal winner to seek a federal court injunction against further proceedings.”). Under the Parsons Steel rule, should SEPTA appear as a party before the Commonwealth Court and raise this Court’s Consent Decree as a res judicata defense to an assessment of highway bridge costs, the Commonwealth Court could reject that defense. Even though, in light of the principles the Third Circuit set forth in Delaware Valley, the Commonwealth Court would clearly be incorrect in doing so, under Parsons Steel, this Court would be compelled to give preclusive effect to the Commonwealth Court’s decision. This situation has not arisen in the present case. Aside from the 1991 decision in SEPTA I with respect to the Woodland Avenue bridge, none of the Commonwealth Court’s rulings have been held by that court to have res judicata effect against SEPTA. Accordingly, SEPTA has good reason to return to this Court to preserve the effect of the Consent Decree. By not becoming a party in a state court action, SEPTA has avoided an adverse res judica-ta ruling. PUC’s argument that SEPTA should litigate this matter in state court thus has no merit. c. Preservation of judgments under the All Writs Act PUC devotes much of its argument to asserting that this Court’s enforcement of the Consent Decree will result in an unmanageable scenario of conflicting judgments. In making this argument, PUC did not consider the fact that this Court retains jurisdiction to enforce its Order. This is the result of the statutory authority available to the Court to enforce its Consent Decree: a combination of the Anti-Injunction Act, 28 U.S.C. § 2283, and the All Writs Act, 28 U.S.C. § 1651. Generally, under the Anti-Injunction Act, a federal court may not enjoin state proceedings. A federal court may, however, stay state court proceedings “where necessary in aid of its jurisdiction, or to protect or effectuate its judgments.” 28 U.S.C. § 2283. The quoted provision “is also known as the ‘relitigation exception’ to the Anti Injunction Act.” In re Prudential Ins. Co. of Am. Sales Practice Litig., 261 F.3d 355, 364 (3d Cir.2001) (quoting Chick Kam Choo v. Exxon Corp., 486 U.S. 140, 147, 108 S.Ct. 1684, 100 L.Ed.2d 127 (1988)). The exception “ ‘was designed to permit a federal court to prevent state litigation of an issue that previously was presented to, and decided by, the federal court.’ ” Id. (quoting Chick Kam Choo, 486 U.S. at 147, 108 S.Ct. 1684); see also, Erwin Chemerinsky, Federal Jurisdiction § 11.2.4 (2d ed.1994) (explaining that the relitigation exception “prevents the harassment of federal court litigants by repetitive state court proceedings” and that it “applies only in situations where because of res judicata the state court should not hear a case, but does so anyway”). The exception applies in this case. As stated by the Third Circuit in the analogous Delaware Valley decision, “in the event of a further attempt” at state-court interference with the federal consent decree, “the Commonwealth parties may avail themselves of remedies ‘to protect and effectuate [United States court] judgments’ permitted under 28 U.S.C. § 2283.” Delaware Valley, 755 F.2d at 45 n. 6. That is exactly the relief SEPTA seeks in this case. The procedural mechanism for this Court’s action under the relitigation exception is the All Writs Act, 28 U.S.C. § 1651. That statute provides in pertinent part: “The Supreme Court and all courts established by Act of Congress may issue all writs necessary or appropriate in aid of their respective jurisdictions and agreeable to the usages and principles of law.” 28 U.S.C. § 1651(a). “The All-Writs Act ‘acts in concert’ with the Anti-Injunction Act ‘to permit the issuance of an injunction.’ ” In re Prudential, 261 F.3d at 365 (quoting Carlough v. Amchem Prods., Inc., 10 F.3d 189, 201 n. 9 (3d Cir.1993)); see also In re Diet Drugs, 282 F.3d 220, 233-35 (3d Cir.2002) (discussing application of relitigation exception to Anti-Injunction Act and All Writs Act). The Court’s use of the All Writs Act