concurring.

In this appeal, we are called on to decide whether the Railway Labor Act (“RLA”) bars Burlington Northern from unilaterally implementing a sniffer dog program designed to restrict alcohol and narcotics use by on-duty railroad workers. The program requires engineers, before embarking on trains from certain yards, to submit their grips to a trained dog to sniff for the presence of controlled substances. Although I concur in the result arrived at by Judge Alarcon’s opinion, I get there by a somewhat different route. First of all, I deal more extensively with the management perogative issued raised by Burlington Northern. Second, I explicitly reject the district court’s “modicum of evidence” approach for determining whether the sniffer dog program is arguably justified by the collective agreement’s implied sensory surveillance provision. Instead, I base my analysis on the arguable intentions of the parties as manifested by custom and practice. I conclude that the program is not justified. Finally, because Burlington Northern raised the “omitted case” doctrine before the district court, I have sought to clarify the doctrine and show that it is inapplicable to the dog sniff procedure.

FACTS

For at least 40 years, Burlington Northern (“BN”) in common with many other railroads, has had a unilaterally implemented safety rule (“Rule G”) prohibiting its employees from using both alcohol and narcotics while on duty and from possessing such substances while on company property. Rule G also bars employees from reporting for duty in a state of intoxication that may in any way impede their ability to perform their work safely. 1 The collective *1108 bargaining agreements between BN and its employees’ unions do not expressly or implicitly refer to Rule G.

Undisputed evidence presented to the district court indicated that, before May 1984, BN relied primarily upon sensory surveillance to enforce Rule G. If an employee’s gait, breath, odor, slurred speech, bloodshot eyes, or errant behavior suggested to a supervisor or security officer that the employee was intoxicated, BN suspended the employee pending a formal investigation under established procedures.

On April 15, 1984 a train crash in Wiggins, Colorado killed, five BN employees and caused $2 million in property damage. The National Transportation Safety Board (“NTSB”) implicated alcohol abuse by an engineer as a possible cause of the accident. On April 21, a train disobeyed an “absolute stop” signal and crashed into a standing train at Newcastle, Wyoming. Two BN employees died and property damage totaled $1 million. A toxicology report indicated that three crew members had marijuana traces in their body fluids.

Following these two serious crashes, BN intensified its efforts to enforce Rule G by introducing two new programs. First, all crew members involved in an accident or operating rule violation were required immediately to attend a clinic and submit to a urinalysis test for the presence of narcotics. Only crew members involved in accidents or operating rule violations demonstrably due to equipment failure were exempted. Moreover, BN’s rules required any employee suspected through sensory surveillance of intoxication to submit to mandatory urinalysis. An employee who refused to submit to mandatory urinalysis was subject to discipline for insubordination. 2

Second, BN contracted for trained sniffer dogs to detect narcotics on its premises. The dog teams visited work places throughout BN’s extensive network. Locations were usually selected by their high incidence of accidents or safety violations, and occasionally the dog teams responded to tips of drug usage. A few locations also were chosen randomly. The dogs checked vehicles in parking lots and were taken through yard offices and company buildings. The dogs also sniffed the “grips” of engineers coming on duty. 3

In conducting the sniffer dog program, the following procedures were employed. A BN supervisor would request the engineer to place the grip on the ground and to step back while the dog sniffed around the grip. If the dog “alerted” on the grip, the supervisor would take the engineer to an office and request that the engineer sign a form consenting to a search of the grip. BN security staff would then searched the grip, its contents, the engineer’s person, and often also the engineer’s car, for narcotics. The dogs did not sniff the engineer. If the engineer refused to consent to a search, the supervisor suspended the engineer from service pending an investigation for a possible Rule G violation. 4

*1109 The Brotherhood of Locomotive Engineers (“BLE”) strenuously opposed the use of the sniffer dogs and urged BN to end the program. BN refused to negotiate. BLE then balloted its branch chairmen on whether to strike on the sniffer dog issue. A majority of respondents voted in favor of a strike.

The district court granted BLE a preliminary injunction on October 5, 1984 prohibiting BN from using the sniffer dogs. After conducting several evidentiary hearings, the court announced its decision in an opinion filed in July 1985. See Brotherhood of Locomotive Engineers v. Burlington Northern Railroad Co., 620 F.Supp. 163 (D.Mont.1985). The district court found that “sensory surveillance by certain supervisory personnel” supported by “at least a modicum of evidence” of intoxication had been established by custom and practice as the only method of enforcing Rule G. The district court further found that this custom and practice constituted an implied term of the collective agreement. 620 F.Supp. at 170-71 . The court stated that “[t]he critical term of [the collective] agreement ... is the term requiring a modicum of evidence that a particular employee was operating under the influence of a prohibited substance, before a supervisor could conduct further investigation.” Id. at 175 .

The court concluded that random use of sniffer dogs was not “arguably justified” under the collective agreement as amended by custom and practice, and thus BN’s use of sniffer dogs, challenged by the unions, constituted a “major dispute” under the RLA requiring the court to enjoin the sniffer dog program. Id. at 172 . BN appealed this decision which is the subject of the instant appeal.

STANDARD OF REVIEW

Whether a matter constitutes a mandatory subject of bargaining under the RLA is a question of law which we review de novo. See Japan Air Lines Co. v. IAM, 538 F.2d 46, 52-53 (2d Cir.1976); cf. NLRB v. International Harvester Co., 618 F.2d 85, 87 (9th Cir.1980). Whether past conduct constitutes custom and practice sufficient to be incorporated as an implied term in a collective agreement covered by the RLA is a question of fact. See Missouri Pacific Joint Protective Board, Brotherhood Railway Carmen of the United States and Canada v. Missouri Pacific Railroad Co., 730 F.2d 533, 537 (8th Cir.1984); cf. Hass v. Darigold Dairy Products Co., 751 F.2d 1096, 1101 (9th Cir.1985) (implied terms in collective agreement under NLRA). We accept a district court’s determination of questions of fact unless clearly erroneous. United States v. McConney, 728 F.2d 1195, 1201 (9th Cir.) (en banc), cert. denied, 469 U.S. 824 , 105 S.Ct. 101 , 83 L.Ed.2d 46 (1984). Whether a dispute constitutes a major dispute or a minor dispute under the RLA is a matter of law which we review de novo. IAM v. Aloha Airlines, Inc., 776 F.2d 812, 815 (9th Cir.1985).

ANALYSIS

BN presents alternative arguments in support of its contention that the district court may not enjoin the dog sniff program. BN first contends that the enforcement of Rule G is a matter entirely within its managerial prerogative. Alternatively, BN contends that the challenged procedure presents not a major but a minor dispute, over which the district court lacks jurisdiction, because: (1) the procedure is arguably justified by an implied-in-fact term of the collective agreement; or (2) the procedure is covered by the omitted case doctrine.

A. Management Prerogative

Neither party disputes the fact that Rule G itself is an implied term of the collective agreement. BN asserts, however, that selecting the method used to enforce a safety rule like Rule G is entirely a matter of management prerogative and not subject to *1110 collective bargaining. BN argues that, because Rule G enforcement is a matter of managerial prerogative, it is not an issue subject to collective bargaining under the RLA. Thus, any prior enforcement practice cannot be an implied condition of the collective agreement or give rise to a labor dispute within the terms of the RLA.

The district court rejected this position. 620 F.Supp. at 169 . I agree with the district court that BN’s management prerogative claim is unfounded.

The RLA requires BN “to exert every reasonable effort to make and maintain agreements concerning rates of pay, rules, and working conditions.” 45 U.S.C. § 152 (emphasis added). No court, however, has comprehensively explained the scope of the statutory phrase “working conditions.”

In Japan Air Lines Co. v. IAM, 538 F.2d 46, 51-53 (2d Cir.1976), the Second Circuit rejected as inconsistent with the legislative history and purpose of the RLA, the union’s assertion that the RLA required the parties to bargain over any lawful proposal advanced by either side. It held that the RLA mandated bargaining only over “rates of pay, rules, and working conditions.” Id. at 52 . Accord IAM v. Northeast Airlines, Inc., 473 F.2d 549 , 556-57 (1st Cir.), cert. denied, 409 U.S. 845 , 93 S.Ct. 48 , 34 L.Ed.2d 85 (1972); Brotherhood of Railroad Trainmen v. Akron and Barberton Belt Railroad Co., 385 F.2d 581, 599 (D.C.Cir.1967), cer t. denied, 390 U.S. 923 , 88 S.Ct. 851 , 19 L.Ed.2d 983 (1968). Therefore, the court upheld the carrier’s management prerogative to determine whether to cease subcontracting ground work at certain airports because the “primary impact” of the union’s proposal did not affect the working conditions of the union’s present members. 538 F.2d at 52 . In so holding, the Second Circuit contrasted Japan Air Lines 's situation with that which existed in Fibreboard Paper Products Corp. v. NLRB, 379 U.S. 203 , 85 S.Ct. 398 , 13 L.Ed.2d 233 (1964), and Order of Railroad Telegraphers v. Chicago North Western Railway Co., 362 U.S. 330 , 80 S.Ct. 761 , 4 L.Ed.2d 774 (1960), in which “the critical question was whether those who were working were to lose their jobs.” 538 F.2d at 52-53 .

The Japan Air Lines approach is simple and pragmatic: if loss of existing employment or employment-related benefits, or potential loss, is the primary impact of the proposal at issue, the RLA requires the parties to bargain over the proposal consistent with the Act’s procedures. I would adopt this approach as the rule of this circuit. Here, a Rule G violation, however discovered, could result in an employee’s discharge. The critical issue in this case is whether the jobs of present employees are jeopardized by the two enforcement programs. Because jobs of present employees are jeopardized, BN's sniffer dog program is a mandatory subject of bargaining under the RLA and may not be implemented unilaterally.

The district court was, therefore, correct to reject BN’s assertion of management prerogative and to reach the question of the nature of the dispute under the RLA.

B. Major v. Minor Dispute

Under the Railroad Labor Act, disputes between railroads and their employees fall into two “sharply distinguished” categories —“major disputes” and "minor disputes.” See Elgin, Joliet & Eastern Railway v. Burley, 325 U.S. 711, 722 , 65 S.Ct. 1282, 1289 , 89 L.Ed. 1886 (1945), aff'd on rehearing, 327 U.S. 661 , 66 S.Ct. 721 , 90 L.Ed. 928 (1946); O’Donnell v. Wien Air Alaska, Inc., 551 F.2d 1141 , 1145-46 (9th Cir.1975) (tracing historical development of RLA). 5

Major disputes arise out of the formation of collective bargaining agreements or unilateral efforts to secure new rights and incorporate them into future agreements. Elgin, 325 U.S. at 723 , 65 S.Ct. at 1290 ; Aloha, 776 F.2d at 815 . Minor disputes involve the interpretation or application of existing collective bargaining agreements. *1111 Elgin, 325 U.S. at 723 , 65 S.Ct. at 1290 ; Aloha, 776 F.2d at 815 . The distinction between minor and major disputes has important procedural consequences.

Generally, major disputes are “left for settlement entirely to the processes of non-compulsory adjustment.” Elgin, 325 U.S. at 723-24 , 65 S.Ct. at 1289-90 . A detailed procedure is provided in 45 U.S.C. §§ 152 , 155, 156, 157, and 160 for moving the dispute through initial conference and negotiation, submission to the National Mediation Board, voluntary arbitration and, possibly, investigation by a special emergency board appointed by the President. See Brotherhood of Railroad Trainmen v. Jacksonville Terminal Co., 394 U.S. 369, 378 , 89 S.Ct. 1109, 1115 , 22 L.Ed.2d 344 (1969). “No authority is empowered to decide the dispute and no such power is intended, unless the parties themselves agree to arbitration.” Elgin, 325 U.S. at 725 , 65 S.Ct. at 1291 . Pending the exhaustion of the Act’s mechanisms for resolving a major dispute, the status quo applies. The duty to maintain the status quo may be enforced by obtaining injunctive relief in a federal district court. See Aloha, 776 F.2d at 816 .

In contrast, minor disputes are subject to compulsory and binding arbitration. See 45 U.S.C. § 153 (first)(i). This task is performed by the National Railroad Adjustment Board or a privately established arbitration panel. See generally Seidenberg, Grievance Adjustment in the Railroad Industry in The Railway Labor Act at Fifty 229-35 (National Mediation Board ed., 1976). The arbitrators have exclusive jurisdiction over minor disputes. See Slocum v. Delaware, Lackawanna & Western Railroad Co., 339 U.S. 239, 244-45 , 70 S.Ct. 577, 579-80 , 94 L.Ed. 795 (1950). Thus, federal courts have no subject matter jurisdiction over minor disputes. Aloha, 776 F.2d at 815 . When only a minor dispute is involved, there is no duty to maintain the status quo and judicial review of the arbitration panel’s decision is extremely limited. See Union Pacific Railroad v. Sheehan, 439 U.S. 89, 91 , 99 S.Ct. 399, 401 , 58 L.Ed.2d 354 (1978) (per curiam).

The test in our circuit for determining if a dispute involves only the interpretation or application of an existing agreement, and is therefore minor, or involves the formation of a collective agreement or a unilateral effort to change working conditions, and is therefore major, derives from Switchmen’s Union of North America v. Southern Pacific Co., 398 F.2d 443 , 447 (9th Cir.1968). See Aloha, 776 F.2d at 815-16 ; O’Donnell, 551 F.2d at 1146-47; Southern Pacific Transportation Co. v. United Transportation Union, 491 F.2d 830, 832 (9th Cir.), cert. denied, 416 U.S. 985 , 94 S.Ct. 2389 , 40 L.Ed.2d 762 (1974). We have reformulated the test several times. See Switchmen’s, 398 F.2d at 447 (only if the disputed action is “in nowise contemplated or arguably covered by the agreement” does it give rise to a major dispute); Southern Pacific Transportation Co., 491 F.2d at 832-33 (A dispute is minor when a contract provision is “reasonably] susceptible” to a party’s interpretation); O’Donnell, 551 F.2d at 1146 (“Is the position of at least one of the parties arguably predicated on the terms of an agreement?”); Aloha, 776 F.2d at 816 (major dispute concerns issue “neither contemplated nor arguably covered” by collective agreement).

The district court accurately summarized the essence of these various reformulations as whether the railroad’s actions are “arguably justified” by the collective agreement between BN and the BLE. See 620 F.Supp. at 175 . If the railroad’s actions are arguably justified, the dispute is a minor dispute; if they are not arguably justified, the dispute is a major dispute. When in doubt, courts construe disputes as minor. See O’Donnell, 551 F.2d at 1146-47 (Switchmen’s test “is not a stringent one”); Brotherhood of Locomotive Engineers v. Atchison, Topeka and Santa Fe Railway Co., 768 F.2d 914, 920 (7th Cir.1985) (citing cases).

1. Sensory Surveillance as Implied-In-Fact Condition to the Collective Agreement

In Detroit and Toledo Shore Line Railroad Co. v. United Transportation Union, 396 U.S. 142, 153 , 90 S.Ct. 294, 301 , 24 *1112 L.Ed.2d 325 (1969) (Shore Line), the Supreme Court held that the scope of the status quo in a major labor dispute includes “those actual, objective working conditions and practices, broadly conceived, which were in effect prior to the time the pending dispute arose and which are involved in or related to that dispute.”

Although Shore Line concerned a dispute that all sides agreed was a major dispute, its teaching applies to all railroad labor disputes — major or minor. The Supreme Court’s holding that the status quo in a major dispute includes employment terms established by past practice means that a railroad collective agreement includes both express terms and terms implied by past practice. See Maine Central Railroad Co. v. United Transportation Union, 787 F.2d 780, 782-83 (1st Cir.) (railroad’s assertion that proposed action comported with past custom and practice was arguably correct and thus dispute was minor), ce rt. denied, — U.S. —, 107 S.Ct. 169 , 93 L.Ed.2d 107 (1986).

Relying on Shore Line, the district court concluded that both Rule G and its customary enforcement by sensory surveillance were implied terms of the collective agreement between BN and BLE. 620 F.Supp. at 170 . The district court found that sensory surveillance by BN’s supervisors had been the only regular method of Rule G enforcement for over forty years and that BLE had long acquiesced in this practice. There is ample evidence in the record to support this conclusion. Several BLE officials with long experience regarding BN’s operating procedures so testified. Moreover, BN never disputed that sensory surveillance by BN’s supervisors was the primary means of detecting Rule G violations before 1984.

The district court also found that BN’s occasional use of sniffer dogs before 1984 did not rise to the level of custom and practice. This conclusion is also supported by the record. See note 4 supra.

Because Rule G enforcement is a mandatory subject of bargaining, and because the district court did not clearly err in finding that sensory surveillance was the customary means of detecting Rule G violations, I would uphold the court’s conclusion that Rule G enforcement by sensory surveillance was an implied condition of the collective agreement.

The district court further determined that the custom and practice of relying on sensory surveillance by BN’s supervisors to detect Rule G violations arguably justifies any reasonable enforcement method based on “a modicum of evidence.” 620 F.Supp. at 171 . In the instant case, the court concluded that such an implied condition did not arguably justify BN’s dog sniff program because engineers subjected to dog sniffs were selected at random, i.e., their selection to determine whether they had violated Rule G was not based on a “modicum of evidence.” Id. at 171-72 .

In my view, the district court’s “modicum of evidence” rationale begs the question. The critical inquiry should not be whether an enforcement procedure is triggered by sufficient objective facts, but whether the parties to this labor dispute, by their conduct, can be said to have agreed to the challenged enforcement procedure. It seems to me farfetched to conclude that the BLE, by acquiescing in Rule G’s enforcement by sensory surveillance of an employee’s gait, 'breath, odor, slurred speech, or blood shot eyes, can be said to have agreed to allow BN to implement any procedure beyond sensory surveillance so long as the procedure is triggered by a “modicum of evidence.”

The kind of sensory surveillance that BN’s supervisors had employed in the past did not implicate the serious privacy intrusions posed by BN’s use of sniffer dogs. I believe that it is incorrect to conclude that the union impliedly agreed to the current use of sniffer dogs just because “through custom and practice” it had for forty years accepted enforcement of Rule G by the non-intrusive procedure of sensory surveillance. Moreover, such sensory surveillance as employed by BN’s supervisors entailed individualized suspicion whereas the use of sniffer dogs rests on group suspicion. The use of sniffer dogs is, in my view, a clear change in working conditions *1113 governed by the collective agreement and, thus, by definition, a major dispute.

It may well be that the use of sniffer dogs is an appropriate response to BN’s safety obligations. However, the merits of the procedure are not before us. I would, therefore, conclude that BN’s use of sniffer dogs is not arguably justified by the implied provision in the collective agreement that BN may enforce Rule G by sensory surveillance.

2. The Omitted Case Doctrine

The Supreme Court first referred to the “omitted case” doctrine in Elgin, Joliet & Eastern Railway v. Burley, 325 U.S. at 723 , 65 S.Ct. at 1290 . An omitted case refers to a “claim founded upon some incident of the employment relation, or asserted one, independent of those covered by the collective agreement, e.g., claims on account of personal injuries.” Id. (emphasis added). If an omitted case is involved, the dispute may be characterized as a minor dispute if it is arguably justified by an implied-in-law provision in the collective agreement.

In rejecting BN’s omitted case argument, the district court noted that an omitted case arises only in a minor dispute, and concluded that, because BN’s use of dog sniffs was a major dispute, it could not be an omitted case. 620 F.Supp. at 172 . This application of the omitted case doctrine is inappropriate because it assumes the result.

As is true of all agreements, a collective bargaining agreement may include terms which, although omitted from the text of the agreement, are nonetheless part of the agreement because they are implied-in-law. Thus, it is necessary to determine whether the sniffer dog program, which is not covered by an express or implied-in-fact provision, is nonetheless arguably justified by an implied-in-law condition. 6

The obligations of the Railroad Safety Act of 1970, as amended, 45 U.S.C. § 431 et seq., and the 230 detailed pages of federal regulations pursuant to the Act, 49 C.F.R. §§ 209.1-236.838 (1985), are implied-in-law conditions of the collective agreement between BN and the BLE. Similarly, the provisions of several earlier acts dealing with railroad safety and their enforcing regulations are all implied-in-law omitted conditions of the collective agreement. *1114 See, e.g., 45 U.S.C. §§ 1-43 (safety appliances and equipment on railroad cars and rail lines); and 45 U.S.C. §§ 61-66 (limitations on hours of service railroad employees).

Federal Railway Administration regulations specifically prohibit any BN employee from using or possessing any controlled substance on railroad property, 49 C.F.R. § 219.101 (a)(1). But, there are no statutes or regulations that authorize or require the railroad to use sniffer dogs to detect employees who use or possess drugs while at work. In short, there is total legislative and administrative silence on this subject. Thus, there is simply no implied-in-law condition that could arguably justify BN's sniffer dog program, and the challenged program, which is outside the ambit of the collective agreement, is a major dispute.

CONCLUSION

The permissible breadth of the measures that an employer may take to ensure that abuse of controlled substances does not impair an employee’s work performance is a relatively novel and controversial issue. In this case, resolution of the issue is made more difficult by the intricacies of the Railway Labor Act, the silence of the express terms of the collective agreement on such matters, and a recognition of the havoc that an intoxicated railroad employee can wreak.

BN’s use of sniffer dogs to enforce Rule G concerns “working conditions” and its primary impact may affect the job security of BN’s employees. Therefore, the district court correctly concluded that the program is a mandatory subject of bargaining.

The district court also correctly concluded that the collective agreement included an implied-in-fact provision based on custom and practice that permitted BN to enforce Rule G through sensory surveillance. Moreover, I agree with the district court, but for different reasons, that this implied provision does not arguably justify a sniffer dog enforcement program. Finally, the Railroad Safety Act and the regulations promulgated thereunder offer no support for the proposition that the sniffer dog program is arguably justified as an implied-in-law condition under the omitted case doctrine. Accordingly, the district court correctly held that the union’s objections to the sniffer dog program presented a major dispute under the RLA. Thus, I vote to affirm the district court’s issuance of an injunction enjoining the program.

. Rule G presently states:

BN unilaterally added the reference to "marijuana, or other controlled substances” in 1980.

.BN's mandatory urinalysis program closely mirrors Federal Railroad Administration ("FRA”) regulations that took effect on November 1, 1985. See 49 C.F.R. § 219 (1985). The district court upheld the FRA regulations over a fourth amendment challenge, and the appeal, Railway Labor Executives’ Association v. Dole, No. 85-2891, was argued before us on the same day as this case and another companion case involving BN's mandatory urinalysis program, Brotherhood oj Locomotive Engineers v. Burlington Northern Railroad Co., No. 85-4137. These cases will be dealt with by separately filed opinions. [ 839 F.2d 575 (9th Cir.1988) and 838 F.2d 1087 (9th Cir.1988).]

. Engineers and train crews are frequently required to spend time away from home. On those occasions, these employees carry their personal belongings in grips.

. The searches were exceptionally thorough, including fanning the engineer’s checkbook, taking the credit cards from his wallet, and checking under the carpet of his car. Two engineers testified that their consent to the searches was involuntary because they understood that a refusal to consent would result in a discharge. Neither of the testifying engineers was charged with a Rule G violation.

Documentary evidence shows that the dog teams operated in fifty locations in 17 states *1109 from May 1984 until October 1984 when the district court preliminarily enjoined the program. The dogs checked the grips of approximately 1000 train crew members, including 250 engineers. The dogs alerted on the grips of 15 engineers; all of the subsequent searches of those grips revealed nothing. The dogs alerted on the grips of 61 non-engineer crewmembers; four positive searches resulted: one produced a bottle of alcohol, and three uncovered narcotics.

. The terms "major dispute” and “minor dispute” are not found anywhere in the RLA. The Supreme Court in Elgin coined the terms as a methodology to be used by courts confronted by disputes arising under the RLA. See Aloha, 776 F.2d at 815 n. 2.

. We first considered the omitted case doctrine in Railway Labor Executives’ Association v. Atchison, Topeka and Santa Fe Railway Co., 430 F.2d 994 (9th Cir.1970), cert. denied, 400 U.S. 1021 , 91 S.Ct. 582 , 27 L.Ed.2d 632 (1971). There Santa Fe obtained the ICC’s approval to discontinue rail service on a certain line. The railroad, however, discontinued the service early, and the union sued for the prematurely displaced workers’ lost wages. We held that the dispute was minor because it involved an interpretation of an omitted provision of the collective agreement.

We concluded that the collective agreement contained

Id. at 996 (emphasis added).

Despite the broad language in Atchison, the omitted case doctrine should only apply to implied-in-law conditions (statutory obligations) and not to implied-in-fact conditions (custom and practice) or conditions deliberately omitted from the collective agreement during earlier negotiations. In Elgin, the Supreme Court described an omitted case as a "claim founded upon some incident of the employment relation, or asserted one, independent of those covered by the collective agreement, e.g., claims on account of personal injuries.” 325 U.S. at 728 , 65 S.Ct. at 1292 (emphasis added). The Court’s example in Elgin must refer to a railroad’s statutory obligation to pay workers’ compensation to injured employees under the Federal Employers’ Liability Act. Therefore, the scope of the omitted case doctrine is narrower than a superficial reading of Atchison might suggest.

In addition, BN contends that Atchison holds that the omitted case doctrine applies whenever the dispute is over a matter not prohibited or sanctioned by a collective agreement. A narrower reading of Atchison is more consistent with the RLA. A holding that any dispute over a matter neither prohibited nor sanctioned by a collective agreement is a minor dispute would reduce the number of major disputes to a small handful and would largely vitiate the major dispute resolution procedures of the Act.