PELL, Circuit Judge.
Consolidated Rail Corporation (Conrail) appeals from judgments entered below, pursuant to jury verdicts, awarding Junior S. Jackson (Jackson) compensatory damages [1047]*1047in the amount of $13,500 for his claim under the Federal Employers’ Liability Act, 45 U.S.C. §§ 51-60 (FELA), and $182,000 pursuant to his pendent claim of retaliatory discharge. Jackson urges on cross-appeal that a punitive damage award of $1,260,000, relating to the retaliatory discharge claim, should be reinstated.
The principal issue on appeal is whether the provisions of the Railway Labor Act (RLA) providing for a scheme of administrative grievance procedures and remedies, 45 U.S.C. § 153 First, preempt the state tort action for retaliatory discharge upon which Jackson relied. If the RLA does preempt the state action, a related issue is whether the preemptive effect is to divest the district court of subject matter jurisdiction over Jackson’s pendent claim, thereby making immaterial Conrail’s delay until after trial in raising the preemption defense.
I. FACTS
Jackson worked as a track maintenance foreman for Conrail. He was a member of the Brotherhood of Maintenance of Railway Employees (Union) and covered by the Union’s collective bargaining agreement.
On August 22, 1980, Jackson filed a two-count complaint against his employer pursuant to the FELA. Jackson alleged that he suffered work-related injuries on or about February 3, 1978 and, as a result, was hospitalized for approximately ten days that month.1
On February 3, 1981, Jackson received a letter from Conrail. The letter advised him that a formal hearing would be held to determine whether he had violated the Railroad Safety Rules by, inter alia, failing to report his alleged injury of February 3, 1978. The hearing was held on February 25, 1981. A transcript of the hearing was sent to the Division Engineer so that he could determine what discipline was to be administered. Hammons, the Division Engineer, had learned previously of Jackson’s 1978 injury because he had received a copy of Jackson’s FELA complaint in November, 1980.2 On April 20, 1981, Hammons issued a notice of discipline, discharging Jackson for failing to report immediately his February 3, 1978 injury to a supervisor as required by Railroad Safety Rule 3000(a) and for lifting beyond his physical capabilities.3
On April 10, 1981, Jackson had amended his claim to add a third count. He charged Conrail with job harassment and the intentional infliction of emotional distress.4 Following his discharge, Jackson indicated that he would again amend his complaint to state a claim of retaliatory discharge and filed an emergency motion seeking to enjoin Conrail from discharging him in retaliation for filing the FELA claim. A hearing was held before Judge Marvin E. Aspen on May 4, 1981. Judge Aspen denied injunc-tive relief, noting that both, Indiana and Illinois recognize a cause of action for retaliatory discharge and that Jackson could be adequately compensated if he succeeded in such an action.
On May 7, 1981, Jackson amended his complaint to add a fourth count alleging retaliatory discharge. He sought $250,000 compensatory damages and $500,000 puni[1048]*1048tive damages. He asserted that the court had pendent jurisdiction over the claim. Conrail did not challenge this jurisdictional basis.
On April 19, 1982, a jury trial commenced b.efore Senior Judge J. Sam Perry. On April 27, 1982, the jury returned its verdicts awarding the plaintiff $13,500 in compensatory damages on the FELA claim, $182,000 compensatory damages on the retaliatory discharge claim, and $1,260,000 punitive damages on that action. Conrail subsequently filed its post-trial motions urging, inter alia, that the district court lacked subject matter jurisdiction over Jackson’s retaliatory discharge claim and that a new trial should be granted because of inflammatory remarks by Jackson’s counsel during opening and closing argument. Prior to filing this motion, Conrail had not objected to the district court’s exercise of pendent jurisdiction over the retaliatory discharge claim.
On July 28, 1982, the district court issued a memorandum order denying all Conrail’s post-trial motions. The court upheld the jury verdicts except for the $1,260,000 punitive damage award which was set aside on the ground that willful, malicious, or oppressive conduct could only be asserted against Jackson’s superior, who was not a party to the action, rather than against Conrail.
Conrail has appealed on the grounds that the district court lacked subject matter jurisdiction over the retaliatory discharge claim and that a new trial is required to determine the amount of compensatory damages because both compensatory awards were tainted by evidence and argument relevant, if at all, only to the question of punitive damages. Jackson urges on cross-appeal that the punitive damage award should be reinstated.
II. SUBJECT MATTER JURISDICTION
Conrail contends that the scheme of administrative remedies and procedures mandated by 45 U.S.C. § 153 First preempts the power of the district court to entertain, pursuant to pendent jurisdiction, Jackson’s claim of retaliatory discharge. Conrail’s argument turns on three analytically distinct points: (1) Jackson’s claim is a variety of wrongful discharge action and, under Andrews v. Louisville & Nashville Railroad Co., 406 U.S. 320, 92 S.Ct. 1562, 32 L.Ed.2d 95 (1972) (Andrews), his exclusive remedy lay with the grievance procedures established pursuant to the collective bargaining agreement and with the National Railroad Adjustment Board (NRAB) created by 45 U.S.C. § 153 First;5 (2) the preemption effected by the RLA divests the district court of subject matter jurisdiction over Jackson’s pendent claim; and (3) because the court below lacked subject matter jurisdiction, Conrail cannot be estopped from raising the issue for the first time in its post-trial motions. Although there is some congruence in the discussion necessitated by the three prongs of Conrail’s argument, we shall discuss each in turn insofar as possible.
A. Preemptive Effect of the RLA
Andrews, upon which Conrail relies, involved a railroad employee who was unable to work for a period after he was involved in an automobile accident. When Andrews believed that he was physically able to return to work, the railroad refused to allow him to return. Andrews severed his connection with the railroad, characterized its refusal to grant him work as a wrongful discharge, and sought relief, in the form of [1049]*1049damages for loss of past and future earnings, in the Georgia state court. After the railroad removed the ease to federal court, both the district court and court of appeals held that Andrews’ tort claim was barred because he had failed to exhaust his administrative remedies under the RLA.
The Supreme Court affirmed the dismissal of Andrews’ suit. Two aspects of the Andrews opinion are particularly relevant to the present case. First, the Court reasoned that Andrews’ claim was a minor dispute, subject to the arbitration remedy provided under the RLA, 45 U.S.C. § 153 First (i), because the collective bargaining agreement was necessarily the source of Andrews’ claim that the discharge was wrongful. The Court noted that, absent the bargaining agreement, Andrews would have been subject to termination at the will of the railroad. 406 U.S. at 324, 92 S.Ct. at 1565. Second, the Court emphasized that exhaustion under the RLA does not mean merely that one must utilize administrative remedies before relitigating the merits of one’s claim in an independent judicial proceeding. Rather, under the RLA, the federal administrative remedy is exclusive. Id. at 325, 92 S.Ct. at 1565.
Jackson urges on appeal that the district judge correctly found his claim to be outside the scope of Andrews and therefore cognizable as a pendent claim in his FELA suit. There is no question that Jackson’s right not to be discharged at the will of Conrail grows out of the collective bargaining agreement. Similarly, there is no doubt that a “retaliatory discharge” is one variety of a “wrongful discharge” claim. Jackson’s argument is that retaliatory discharge implicates certain rights that distinguish it sufficiently from the discharge in Andrews to place Jackson’s claim outside the scope of the Andrews holding. Whether this is true is a question of first impression. The arguments and case law upon which Jackson relies are best grouped into two lines of analysis: (1) that his retaliatory discharge claim vindicates a federal FELA right, and (2) that an exception to preemption is justified in this case by Farmer v. United Brotherhood of Carpenters, Local 24, 430 U.S. 290, 97 S.Ct. 1056, 51 L.Ed.2d 338 (1977). We discuss each in turn.6
1. Vindication of Federal Right.
Jackson analogizes this case to those in which a claim based on a federal statute has been upheld, despite petitioner’s failure to exhaust administrative remedies under the RLA or to obtain relief pursuant to those remedies. E.g., Barrentine v. Arkansas-Best Freight System, Inc., 450 U.S. 728, 101 S.Ct. 1437, 67 L.Ed.2d 641 (1981); Johnson v. American Airlines, Inc., 487 F.Supp. 1343 (N.D.Tex.1980). Jackson reasons that he had a federal statutory right to bring an FELA suit, 45 U.S.C. § 51, and that suffering discharge in retaliation for bringing such a suit has an impermissible impact on his federal right.
In Johnson v. American Airlines, Inc., 487 F.Supp. 1343 (N.D.Tex.1980), former commercial airline pilots challenged American’s rule that made retirement of pilots mandatory at age sixty. The former pilots wanted to continue working for American as flight engineers. Flight engineers were not subject to the age sixty retirement rule. The district court held that the pilots’ suit, based on the Age Discrimination in Employment Act, 29 U.S.C. § 623 (ADEA), was cognizable even though the plaintiffs had not exhausted the applicable remedies under the collective bargaining agreement or the RLA. The court relied on the holding in Alexander v. Gardner-Denver Co., 415 U.S. 36, 45, 94 S.Ct. 1011, 1018, 39 L.Ed.2d 147 (1974), in which the Court stated that an arbitrator’s resolution of a contractual [1050]*1050claim is not necessarily dispositive of a statutory claim premised on Title VII. Johnson, 487 F.Supp. at 1345. The Johnson court noted that exhaustion of administrative remedies was not a condition precedent to maintaining an ADEA suit because the right not to suffer from age discrimination is a federal statutory right rather than a contractual right. Id. at 1346. See also Barrentine v. Arkansas-Best Freight System, Inc., 450 U.S. 728, 101 S.Ct. 1437, 67 L.Ed.2d 641 (1981) (wage claims based on Fair Labor Standards Act, 29 U.S.C. §§ 201-219, not barred by prior submission of grievances to contractual dispute resolution procedures); Conrad v. Delta Airlines, Inc., 494 F.2d 914 (7th Cir.1974) (distinguishing Andrews from Conrad’s allegations that Delta discharged him, in violation of the express provisions of 45 U.S.C. § 152 Fourth, because of his union activities).
The present case is distinguishable from Barrentine, Conrad, and Johnson because neither the FELA, the RLA, nor any other federal statute specifically provides a right of action to one discharged under the circumstances alleged by Jackson. The question is whether the state tort action for retaliatory discharge, buttressed by the policies underlying the FELA, is sufficiently analogous to a federal statutory right to rebut the preemption of the RLA.
The case most relevant to resolving this issue is Hendley v. Central of Georgia Railroad, 609 F.2d 1146 (5th Cir.1980), cert. denied, 449 U.S. 1093, 101 S.Ct. 890, 66 L.Ed.2d 822 (1981). Hendley brought suit to enjoin the railroad for which he worked from conducting a disciplinary hearing relating to his alleged disloyalty in assisting a fellow employee’s FELA action against the railroad. Hendley relied on 45 U.S.C. § 60 which provides that it is a crime to discipline an employee for voluntarily furnishing information in connection with an FELA case. The district court in Hendley had ruled that his claim was a minor dispute, within the exclusive jurisdiction of the NRAB, because the FELA case was already concluded and there was no possibility that relevant evidence would be suppressed through coercion by the railroad.
Several factors were relevant to the Fifth Circuit’s holding that Hendley’s claim was cognizable in federal court. The court noted that the case involved interpretation of a federal statute because it was necessary to determine whether 45 U.S.C. § 60 was applicable after the FELA action was concluded. The Fifth Circuit also analogized Hendley to Brotherhood of Railroad Trainmen v. Central of Georgia Railway, 305 F.2d 605 (5th Cir.1962) (Brotherhood), in which the plaintiff had alleged that a disloyalty investigation by the railroad was instituted in order to discredit the union of which he was a representative. Because these allegations constituted, if proven, a violation of 45 U.S.C. § 152 Third, which prohibits coercion in the employees’ choice of a representative, the Fifth Circuit had held that it had jurisdiction over the case. The Hendley court explicitly distinguished Brotherhood from a later Fifth Circuit disposition, Brotherhood of Railroad Trainmen v. Southern Railway, 393 F.2d 303 (5th Cir.1968) (Southern), in which the plaintiff had relied on the general policy provisions of the RLA. The Southern court had held that jurisdiction could not be premised on such a general policy statement. Hendley, 609 F.2d at 1152 n. 4.
The Hendley decision therefore recognizes an exception to preemption only if the suit is premised on a specific federal statutory section. It distinguishes such a claim from one in which the allegations constitute, if proven, only a violation of the policy underlying a federal statute. This distinction, recognized in Hendley, strongly suggests that the statutory procedures and remedies of the RLA are not rebutted in Jackson’s case.
There is admittedly a superficial appeal to reasoning that the FELA, particularly those sections stating the right to sue, 45 U.S.C. § 51, and the prohibition against coercing an employee not to volunteer information relative to a fellow employee’s FELA action, id. § 60, prohibits an employer from discharging an employee in retaliation for filing an FELA action. Such a [1051]*1051statute has not, however, been enacted by Congress.
In a case like this involving a railway worker subject to the RLA, yet entitled to rely upon the FELA, there is a tension between the two federal statutes. In such a context, a court must be particularly reluctant to elevate an FELA policy to the status of a federal right. Such caution is illustrated by Bay v. Western Pacific Railroad, 595 F.2d 514 (9th Cir.1979), in which the court held that the language of 45 U.S.C. § 55, which, inter alia, declares “void” any “device” utilized by a common carrier to exempt itself from FELA liability, provides no private cause of action for an employee allegedly discharged in retaliation for filing an FELA action. That Jackson’s claim is separately grounded in a state cause of action is immaterial because it is only federal statutory rights that have been held, under cases such as Barrentine, Hendley, Conrad, and Johnson, to rebut the preemption of the RLA. See De La Rosa Sanchez v. Eastern Airlines, Inc., 574 F.2d 29 (1st Cir.1978) (holding pension claim based on law of Puerto Rico subject to exclusive jurisdiction of the RLA despite alleged federal interest, embodied in the Employee Retirement Income Security Act of 1974, in fulfillment of pension obligations). We therefore concur with the distinction recognized by the Hendley court between cases premised on a federal statutory provision and those premised on a federal policy and hold that the policies underlying the FELA do not overcome the RLA mandate that Jackson’s exclusive remedy lay with administrative grievance procedures.7
2. Farmer Exception to Preemption.
The second argument urged by Jackson is that the “outrageous” conduct of Conrail requires recognition of an exception to the preemption doctrine in this case as it did in cases such as Farmer v. Brotherhood of Carpenters, Local 25, 430 U.S. 290, 97 S.Ct. 1056, 51 L.Ed.2d 338 (1977) (Farmer); and Sears, Roebuck & Co. v. San Diego County District Council of Carpenters, 436 U.S. 180, 98 S.Ct. 1745, 56 L.Ed.2d 209 (1978) (Sears). In both Farmer and Sears, the Supreme Court held that state claims were cognizable because they were not preempted by the federal labor laws.
In Farmer, the Court held that a California state court could exercise jurisdiction over the claim of a local union officer alleging intentional infliction of emotional distress. Hill, the petitioner’s decedent, had alleged that, as a result of disagreement with other union officials, he was subjected to a campaign of ridicule and personal abuse and was discriminated against by the union hiring hall. After reviewing exceptions to the preemption doctrine recognized in earlier' cases, Farmer, 430 U.S. at 295-97, 97 S.Ct. at 1060-61, the Court stated that one must determine the scope of the general preemption rule “by examining the state interests in regulating the conduct in question and the potential for interference with the federal regulatory scheme.” Id. at 297, 97 S.Ct. at 1061.
In applying this test to Hill’s claim, the Court first noted that the state had a substantial interest in protecting its citizens from the alleged outrageous conduct. Id. at 302, 97 S.Ct. at 1064. The Court recognized that, because the abusive conduct was intertwined with allegations of hiring hall discrimination, there was some potential that Hill’s state claim would touch on areas generally within the exclusive jurisdiction [1052]*1052of the National Labor Relations Board (NLRB). This potential interference did not overcome the state’s interest, however, because resolution of the state tort suit turned on whether the union’s actions had caused Hill severe emotional distress whereas the focus of an unfair labor practice inquiry would have been on whether the union’s conduct discriminated against Hill in terms of employment opportunities. As a result, the tort action could be resolved “without reference to any accommodation of the special interests of unions and members in the hiring hall context.” Id. at 305, 97 S.Ct. at 1066.
Similarly, in Sears, the Court held that Sears could rely on state trespass laws in seeking an injunction against union picketing on its private property. As in Farmer, the primary focus of the Sears Court was on whether recognition of the state trespass law would interfere with the federal regulatory scheme. The Court stated:
The critical inquiry, therefore, is not whether the State is enforcing a law relating specifically to labor relations or one of general application but whether the controversy presented to the state court is identical to (as in Gamer) or different from (as in Farmer) that which could have been, but was not, presented to the Labor Board.
Id. 436 U.S. at 197, 98 S.Ct. at 1757. Applying this test to the facts presented in Sears, the Court found that the focus of the state trespass proceeding would be on where the picketing occurred — private property— whereas the focus of an unfair labor practice proceeding would have been on the objective of the picketing. Id. at 198, 98 S.Ct. at 1758.8
Sears and Farmer both raised questions of preemption under the National Labor Relations Act, 29 U.S.C. §§ 151-166 (NLRA), rather than under the RLA. Although this does not mean that the test articulated in Farmer and refined in Sears is inapplicable to the preemption issue in the present case, the difference between the impact of the NLRA and the RLA has significance. The focus of the NLRA is on specific conduct that Congress has deemed subject to either prohibition or protection, 29 U.S.C. §§ 157-158. Often, as illustrated by Sears, it is the objective of certain conduct, rather than the mere exercise thereof, that is relevant to determining whether actions are protected or prohibited by the NLRA. In contrast, the RLA has made any grievance arising out of the collective bargaining agreement subject to the exclusive arbitral remedies contained in that Act, 45 U.S.C. § 153 First (i). It follows from this difference that a state claim is more likely to impinge on an area of exclusive administrative jurisdiction under the RLA than under the NLRA.9
The lower court cases that have applied the Farmer test in the RLA context illustrate this result. For instance, in Magnuson v. Burlington Northern, Inc., 576 F.2d 1367 (9th Cir.1978), cert. denied, 439 U.S. 930, 99 S.Ct. 318, 58 L.Ed.2d 323, the plaintiff sued the defendant railroad and officers thereof in state court, alleging intentional infliction of emotional distress. The gravamen of Magnuson’s complaint was that his discharge, following a head-on collision between two freight trains, was part of a [1053]*1053conspiracy to cover up the railroad’s own negligence which was responsible for the accident. After removal to the federal court, the district judge dismissed Magnu-son’s complaint on the ground that it was subject to the exclusive jurisdiction of the dispute resolution processes established by the RLA. Id. at 1368.
The Ninth Circuit affirmed the dismissal. In distinguishing Farmer, upon which Magnuson relied, the majority stated: “Unlike Farmer, this action is based on a matrix of facts which are inextricably intertwined with the collective bargaining agreement and the R.L.A.” Id. at 1369. The court noted that both the wrongful discharge aspects of Magnuson’s claim and those pertaining to the propriety of the investigation and hearing had a “ ‘not obviously insubstantial relationship to the labor contract.” Id. at 1369-70.
Similarly, in Majors v. U.S. Air, Inc., 525 F.Supp. 853 (D.Md.1981), the district court distinguished Farmer in concluding that jurisdiction over Majors’ state claims for defamation and false imprisonment was precluded by the RLA. Majors’ claims arose from an investigation conducted by the airline into whether he had stolen airline property. The district judge found that because his claim was based on some incident of the employment relationship, it was subject to the RLA. Id. at 857; see also Carson v. Southern Railway, 494 F.Supp. 1104, 1112 (D.S.C.1979) (state defamation claim is “in essence and substance” an employment grievance solely within the jurisdiction of the NRAB); Pandil v. Illinois Central Gulf Railroad, 312 N.W.2d 139, 143 (Iowa App.1981) (facts relevant to plaintiff’s claim of wrongful denial of recall from furlough status “inextricably intertwined with the grievance procedures of the collective bargaining agreement” and therefore preempted by the RLA).
In applying Farmer to the instant case, we must examine “the state interest in regulating the conduct in question and the potential for interference with the federal regulatory scheme.” 430 U.S. at 297, 97 S.Ct. at 1061. First, we note that the district court found that Indiana recognized a tort action for retaliatory discharge in Frampton v. Central Indiana Gas Co., 260 Ind. 249, 297 N.E.2d 425 (1973).10 The plaintiff in Frampton had been a terminable-at-will employee. She filed a claim pursuant to the Indiana Workmens’ Compensation Act of 1929, Ind.Code §§ 22-3-2-1— 22-3-6-3, when she learned of a thirty percent loss of use in her arm as the result of a work-related injury. She received a settlement for her injury. Approximately one month later, she was discharged without any reason being given. The Indiana Supreme Court upheld Frampton’s cause of action, stating: “[W]hen an employee is discharged solely for exercising a statutorily conferred right an exception to the general rule [that, under ordinary circumstances, an employee-at-will may be discharged without cause] must be recognized.” 297 N.E.2d at 428.
It is significant that Frampton was a terminable-at-will employee whereas Jackson was not. Although no Indiana court has addressed whether an employee subject to a union collective bargaining agreement can sue for retaliatory discharge, other courts have limited the action to employees-at-will, reasoning that the retaliatory discharge action provides the only means for such an employee to seek redress. Eg., Cook v. Caterpillar Tractor Co., 85 Ill.App.3d 402, 40 Ill.Dec. 864, 407 N.E.2d 95 (1980). Contra, Wyatt v. Jewel Companies, Inc., 108 Ill.App.3d 840, 64 Ill.Dec. 388, 439 N.E.2d 1053 (1982) (refusing to follow Cook).
Conrail has waived any challenge to Jackson’s claim on the ground that it fails to state a cause of action. We need not re[1054]*1054solve, therefore, whether the Indiana court would extend Frampton to provide Jackson, an employee who could seek relief pursuant to the collective bargaining agreement, a cause of action for retaliatory discharge. Recognizing that this issue is not clearly resolved is, however, a point of law that this court must consider in determining the state’s interest in providing Jackson a judicial forum for his claim.
The second inquiry mandated by Farmer is the potential interference with the federal regulatory scheme. It is established under Andrews that a claim of wrongful discharge is subject exclusively to the administrative remedies established by the RLA. 406 U.S. at 325, 92 S.Ct. at 1565. Conrail defended against Jackson’s retaliatory discharge claim by urging that he was discharged for cause: the violation of Railroad Safety Rules. The inquiry mandated by these two varying explanations of Jackson’s dismissal must focus to a significant extent on the validity of Conrad’s defense. As such, it is precisely the sort of inquiry required in any wrongful discharge action. Because Jackson’s claim could not be resolved by examining only his FELA rights, it is abundantly clear that resolution of his suit impinges on those areas left, under the RLA, to exclusive administrative resolution. The claim raised by Jackson, pursuant to Indiana law, is identical to the claim he would have made, had he pursued the grievance through administrative channels, and therefore the potential interference with the federal regulatory interest is too great, under Sears, 436 U.S. at 197, 98 S.Ct. at 1757, to permit an exception to the preemption doctrine.
B. Impact of the Preemption on the District Court’s Subject Matter Jurisdiction
Having determined that Jackson’s claim is within the scope of Andrews and that his state tort remedy is accordingly preempted by the RLA, we turn to whether the effect of preemption in this case is to divest the district court of subject matter jurisdiction over Jackson’s pendent claim.
In Farmer, the Supreme Court clarified, in the NLRA context, the relationship between preemption and jurisdiction:
“[I]n referring to decisions holding state laws pre-empted by the NLRA, care must be taken to distinguish pre-emption based on federal protection of the conduct in question ... from that based predominantly on the primary jurisdiction of the National Labor Relations Board ..., although the two are often not easily separable.” Railroad Trainmen v. Jacksonville Terminal Co., 394 U.S. 369, 383 n. 19 [89 S.Ct. 1109, 1118 n. 19, 22 L.Ed.2d 344] (1969). The branch of the pre-emption doctrine most applicable to the instant case concerns the primary jurisdiction of the National Labor Relations Board.
430 U.S. at 295 n. 5, 97 S.Ct. at 1060 n. 5. The distinction made by the Farmer Court, considered together with the emphasis in Andrews on the exclusivity of the remedy provided, under the RLA, by the administrative procedures, compels the conclusion that the preemption at issue in this case relates to the subject matter jurisdiction of the court below. Numerous courts concur in this conclusion. For instance, in Hendley v. Central of Georgia Railroad, 609 F.2d 1146, 1150 (5th Cir.1980), cert. denied, 449 U.S. 1093, 101 S.Ct. 890, 66 L.Ed.2d 822 (1981), the court observed that the NRAB has “exclusive jurisdiction over this dispute, unless 45 U.S.C. § 60 is found to override the statutory arbitration processes.” In de la Rosa Sanchez v. Eastern Airlines, Inc., 574 F.2d 29, 32 (1st Cir.1978), the court stated: “No federal or state court has jurisdiction over the merits of any employment dispute subject to determination by a system board of adjustment.” The Maryland district court has similarly observed that “this Court’s jurisdiction is still preempted because of the threat of interference with a federal regulatory scheme.” Majors v. U.S. Air, Inc., 525 F.Supp. 853, 856 (D.Md.1981); see also Carson v. Southern Railway, 494 F.Supp. 1104, 1112 (D.S.C.1979) (dismissal for lack of subject matter jurisdiction).
Consistent with the foregoing authorities, we hold that the court below lacked subject [1055]*1055matter jurisdiction to entertain Jackson’s pendent claim.
C. Estoppel Regarding Lack of Subject Matter Jurisdiction
The question remains whether Conrail is estopped, by its previous consent to the exercise of jurisdiction by the district court over Jackson’s pendent claim, from raising the preemption of subject matter jurisdiction for the first time in its post-trial motions and, now, on appeal.
The general rule is that subject matter jurisdiction may be challenged by a party or raised sua sponte by the court at any point in the proceedings. E.g., American Fire & Casualty Co. v. Finn, 341 U.S. 6, 16-19, 71 S.Ct. 534, 541-42, 95 L.Ed. 702 (1951); Sadat v. Mertes, 615 F.2d 1176, 1188 (7th Cir.1980); Fed.R.Civ.P. 12(h)(3). The corollary to this rule is that “subject jurisdiction otherwise lacking cannot be conferred by consent, collusion, laches, waiver, or estoppel.” Sadat v. Mertes, 615 F.2d 1176, 1188 (7th Cir.1980).
Two of the cases upon which Jackson relies are inapposite because the courts determined that they did have subject matter jurisdiction over the claim. See Zipes v. Trans World Airlines, Inc., 455 U.S. 385, 102 S.Ct. 1127, 71 L.Ed.2d 234 (1982); United States v. Edwards, 23 F.2d 477 (8th Cir.1927).
The final case relied upon by Jackson in support of his claim that Conrail is estopped from raising the issue of subject matter jurisdiction is DiFrischia v. New York Central Railroad, 279 F.2d 141 (3d Cir.1960). In DiFrischia, the Third Circuit held that the defendant railroad was estopped from urging, twenty-three months after inception of the case, that diversity of citizenship between the parties, and therefore subject matter jurisdiction, was lacking.
Although the DiFrischia court does not elaborate at length as to the legal basis for its recognition of an exception to the general rule that the doctrine of estoppel is inapplicable to the issue of subject matter jurisdiction, the Third Circuit’s reference to Young v. Handwork, 179 F.2d 70 (7th Cir.1949), cert. denied, 339 U.S. 949, 70 S.Ct. 805, 94 L.Ed. 1363 (1950), suggests that the court viewed the determination of a party’s citizenship as a question of fact and therefore distinct from the legal question whether subject matter jurisdiction was demonstrated. Estoppel was therefore applicable because it went to a question of fact rather than to the determination of jurisdiction. See Young, 179 F.2d at 73 (“ ‘place of residence is a question of fact and not a question of law, and that question of fact has been settled in this court’ ” (quoting district judge in Young)).
DiFrischia is not persuasive support for Jackson’s contention that Conrail is es-topped from raising the preemptive effect of the RLA. The issue in DiFrischia involved diversity of citizenship, not preemption by federal law. Insofar as the rationale of DiFrischia turns on the distinction between the factual question of citizenship and the legal determination regarding jurisdiction, DiFrischia is clearly inapplicable to this case.
Further, this court has previously held, in a case involving diversity of citizenship, that it would not extend DiFrischia beyond its specific facts. Sadat v. Mertes, 615 F.2d 1176, 1188 (7th Cir.1980). In so holding, the Sadat court was in accord with the weight of authority. See C. Wright, A. Miller & E. Cooper, Federal Practice & Procedure § 3522, at 50-52 & 52 n. 25 (1975) (noting that the significance of DiFrischia as general precedent is “dubious,” id. at 50, and that in more recent cases, the Third Circuit has either distinguished or ignored DiFrischia, id. at 52). Even if DiFrischia remains viable precedent, to apply that case’s rule in the present situation, in which diversity jurisdiction is not at issue, would extend it far beyond its specific facts. Consistent with our conclusion in Sadat, 615 F.2d at 1188, we decline to do so.
While we in no way condone the failure of Conrail to raise earlier the dispositive question of whether subject matter jurisdiction over Jackson’s pendent claim of retaliatory discharge is preempted by the RLA, [1056]*1056this case is governed by the general rule that the question of jurisdiction may be raised at any point in the proceedings. Id. For that reason, Conrail is not estopped from raising the jurisdictional issue for the first time in its post-trial motions before the district court.
III. REMAINING ISSUES RAISED BY THE PARTIES
In light of our conclusion that the district court lacked subject matter jurisdiction over Jackson’s retaliatory discharge claim, that claim must be dismissed and the judgment of compensatory damages awarded pursuant to that claim vacated. Our resolution of the jurisdictional question necessarily precludes Jackson’s assertion on cross-appeal that the punitive damage award pursuant to the retaliatory discharge claim should be reinstated.
The only remaining issue therefore is whether the compensatory damage award of $13,500 pursuant to Jackson’s FELA claim must be vacated and a new trial on damages granted. Conrail claims that the award was “tainted” by counsel’s argument and evidence appropriate, if at all, only to the question of punitive damages.
The evidence and argument of which Conrail complains pertains to Conrail’s net worth, the number of persons in Jackson’s family, impliedly dependent upon him for support, and counsel’s characterization of the case as an opportunity for the jury to send a message in favor of all working men to corporations throughout the country.
Conrail’s argument is untenable because we find no indication that the FELA compensatory damage award was tainted. It is significant that the damages awarded Jackson on the FELA claim, $13,500 after a ten percent reduction for Jackson’s contributory negligence, is less than eight percent of the compensatory damages awarded on the retaliatory discharge claim. Even more striking, it is just over one percent of the punitive damages awarded Jackson on the retaliatory discharge claim. These comparisons compel the conclusion that the jury properly considered the FELA claim wholly separate and apart from the retaliatory discharge claim for the purpose of setting a damage figure and therefore no tainting occurred.
If any error did occur below pertaining to the admission of evidence or the tolerance of impermissible argument, a question that we do not decide, the error was harmless. The compensatory damage award of $13,500 in favor of Jackson on his FELA claim will not be disturbed on appeal.
CONCLUSION
A federal interest embodied in the policies, but not the specific statutory provisions, of the FELA is insufficient to rebut the persuasive preemption of the RLA over Jackson’s retaliatory discharge claim. Similarly, Farmer v. Brotherhood of Carpenters, Local 25, 430 U.S. 290, 97 S.Ct. 1056, 51 L.Ed.2d 338 (1977), does not support recognition of an “exception” to the preemption doctrine in this case because resolution of Jackson’s claim requires consideration of the same issues that Jackson would have raised before an administrative tribunal had he pursued the grievance procedures of the collective bargaining agreement and the RLA.11
[1057]*1057The preemptive effect of the RLA is to divest the court below of subject matter jurisdiction and, consistent with the general rule that subject matter jurisdiction may be challenged at any point in the proceedings, Conrail is not estopped from raising that issue for the first time after the jury had returned its verdicts.
The jury award of compensatory damages for Jackson’s FELA claim shows no evidence of “tainting” by the admission of improper evidence or argument.
This cause is remanded to the district court with instructions to vacate the judgment and award of compensatory damages in favor of Jackson on his retaliatory discharge claim and to dismiss that claim for lack of subject matter jurisdiction. The judgment in favor of Jackson on the FELA claim is affirmed. Each party shall bear its own costs on appeal. We express no view as to the allocation of costs reached by the judge below relative to the district court proceedings.
Reversed In Part; Affirmed In Part.