PUBLISHED

UNITED STATES COURT OF APPEALS

FOR THE FOURTH CIRCUIT

No. 22-1912

DAWN C. POLK

 Plaintiff - Appellant

v.

AMTRAK NATIONAL RAILROAD PASSENGER CORPORATION; ANDREW 

COLLINS, Amtrak D.ER; ALTON LAMONTAGNE, Roadforeman Manager; 

TRACEY ARMSTRONG, Trainmaster Manager

 Defendants - Appellees.

Appeal from the United States District Court for the District of Maryland at Baltimore. 

Lydia Kay Griggsby, District Judge. (1:21−cv−01740−LKG)

Argued: March 9, 2023 Decided: April 26, 2023

Before WILKINSON, AGEE, and HEYTENS, Circuit Judges.

Affirmed by published opinion. Judge Wilkinson wrote the opinion, in which Judge Agee 

and Judge Heytens joined.

ARGUED: Denise M. Clark, CLARK LAW GROUP, PLLC, Washington, D.C., for 

Appellant. Alison Nadine Davis, LITTLER MENDELSON P.C., Washington, D.C., for 

Appellees. ON BRIEF: Rosa T. Goodman, LITTLER MENDELSON, P.C., Washington, 

D.C., for Appellees.

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WILKINSON, Circuit Judge:

Congress enacted the Railway Labor Act (RLA), 45 U.S.C. §§ 151 et seq., to curb

disruption of the rail yards, tracks, and terminals that tie our economy together. As relevant 

here, the statute directs workers and carriers to resolve their differences through mediation 

and arbitration. But Dawn Polk, a rail worker, elected to sue her employer, Amtrak, in 

federal court. The district court, however, held that Polk’s claims were subject to arbitration 

under the RLA. We agree and thus affirm the judgment.

I.

Dawn Polk, an African American woman, worked as a conductor for Amtrak 

National Railroad Passenger Corporation (Amtrak). During her employment, she belonged 

to a division of the Sheet Metal, Air, Rail and Transportation Workers (SMART) union, 

which maintained a collective bargaining agreement (CBA) with Amtrak.

In late 2018, Polk suffered an injury that caused her to miss multiple months of 

work. Before returning to the job, Polk was required to take a drug test in accordance with

Amtrak’s Drug and Alcohol-Free Workplace Program (Drug-Free Program). The Program

specifies that “[a]ny employee returning to work after an absence of at least 30 consecutive 

days . . . must pass a [d]rug test before returning to work.” J.A. 314.

On March 25, 2019, an Amtrak representative called Polk and asked her to take the 

drug test that day. Polk promptly went to the testing site but was unable to produce an 

adequate sample of urine during an allotted three-hour period. She then called Andrew 

Collins, Amtrak’s director of employee relations, to ask to reattempt the test the following 

morning. According to Polk, Collins responded that “you don’t get a second test” and 

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advised her to undergo a medical evaluation for shy bladder syndrome. J.A. 26. After 

Polk’s subsequent assessment for shy bladder syndrome came back negative, Amtrak 

terminated her employment pending an investigative hearing.

A couple of weeks later, on April 19, Amtrak extended Polk a settlement offer via

her union representative. Per the offer, which the parties refer to as “the Waiver,” Amtrak 

proposed to reinstate Polk so long as she agreed to several conditions including that she 

waive her right to the investigative hearing. The Waiver also obligated Polk to see a 

substance abuse professional, undergo “unannounced drug and/or alcohol follow-up testing 

at least six (6) times for a period of twelve (12) months,” and “waiv[e] all rights under the 

Collective Bargaining Agreement” in the event of a future violation of the Drug-Free 

Program. J.A. 55–56. Polk alleges that she signed the Waiver “under duress.” J.A. 28. 

Polk returned to work on May 8, six weeks after the initial drug test. She alleges 

that she received four drug tests over the following year, and then another seven tests in

the year after that. As the tests continued into the second year following her reinstatement, 

Polk expressed concern to her union that Amtrak was testing her beyond the twelve-month

period mentioned in the Waiver. Polk alleges that the added tests caused her embarrassment

and interfered with her medical appointments.

In early 2021, Polk collected her concerns into a formal grievance that she filed with 

Amtrak’s dispute resolution office. She alleges that she subsequently received a call from 

an Amtrak representative attributing the continued testing to a computer entry error. Polk 

further alleges that the representative “never called . . . back as promised” and failed to 

rectify the error. J.A. 32. Two months later, Polk retired from Amtrak on disability benefits. 

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In July 2021, Polk brought the instant lawsuit pro se in the District of Maryland. 

She named Amtrak and Collins as defendants, along with three other Amtrak colleagues,

Alton Lamontagne, Curtis Stencil, and Tracey Armstrong. Polk asserted state-law claims 

of breach of contract and tort, as well as a federal claim of racial discrimination in violation 

of Title VII of the Civil Rights Act of 1964, 42 U.S.C. §§ 2000e et seq. She requested $1.5 

million in damages. 

Defendants moved to dismiss, and Polk in turn moved for summary judgment as 

well as for leave to amend her complaint. In June 2022, the district court granted 

defendants’ motion and denied Polk’s two motions. It reasoned that the Railway Labor Act 

preempted Polk’s state-law claims and precluded her federal Title VII claim because all of 

these claims would “require that the Court interpret the rights within the CBA” between 

Amtrak and SMART. J.A. 362.

Polk timely appealed.

II.

This appeal concerns the Railway Labor Act, which aims to “avoid any interruption 

to commerce” and “provide for the prompt and orderly settlement” of disputes between rail 

workers and carriers. 45 U.S.C. § 151a. In relevant part, the statute sets forth a detailed 

dispute-resolution procedure, culminating in arbitration, for conflicts “growing out 

of . . . the interpretation or application” of a collective bargaining agreement. Id. § 153

(first). Such conflicts are known as “minor disputes.” Hawaiian Airlines, Inc. v. Norris, 

512 U.S. 246, 252–53 (1994); see Consol. Rail Corp. v. Ry. Lab. Executives’ Ass’n, 491 

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U.S. 299, 302 (1989) (“[M]ajor disputes seek to create contractual rights, minor disputes 

to enforce them.”).

The Supreme Court has held that the RLA’s arbitral procedure for minor disputes is

“mandatory.” Hawaiian Airlines, 512 U.S. at 252. Thus, minor disputes that are not 

resolved through an intra-carrier grievance procedure are to be referred to arbitration. For 

the hearing of these matters, the RLA created the National Railroad Adjustment Board, a

specialized tribunal consisting equally of union and carrier representatives. 45 U.S.C. 

§ 153 (first). Carriers and unions may also institute their own adjustment boards instead 

with a single representative from each side. Id. § 153 (second). To secure the RLA’s 

arbitral procedure, the Supreme Court has ruled that the RLA preempts state-law claims

that also constitute minor disputes. Hawaiian Airlines, 512 U.S. at 262–63.

III.

On appeal, Polk solely challenges the district court’s holding that the RLA precludes

her Title VII claim. At the dismissal stage, we review the district court’s decision de novo. 

AFSCME Md. Council 3 v. Maryland, 61 F.4th 143, 148 (4th Cir. 2023). Polk argues that 

the RLA does not preclude her Title VII claim because the claim is not a minor dispute. 

She advances two arguments. First, Polk maintains that Title VII claims are “never” minor 

disputes because Title VII supplies an “independent” cause of action. Appellant Opening 

Br. at 4. Second, and in the alternative, Polk contends that at least her particular claim is

not a minor dispute because it does not require the “interpretation or application” of a CBA.

45 U.S.C. § 153 (first). We address each of Polk’s contentions in turn.

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A.

Polk first argument is categorical. She contends that all Title VII claims are 

intrinsically different from RLA minor disputes because Title VII “rights are guaranteed 

to employees whether or not a collective bargaining agreement exists.” Appellant Opening 

Br. at 9. Polk’s proposition that a Title VII claim cannot be a minor dispute, however, runs 

headlong into Supreme Court guidance, circuit court precedent, and the congressional 

judgments behind the RLA. While Polk is entitled to seek a remedy for workplace

discrimination, the RLA accords her the avenue for such relief in arbitration.

1.

The Supreme Court has indicated that federal claims, such as those arising under 

Title VII, can constitute minor disputes. On multiple occasions, the Court has explained 

that state causes of action can be minor disputes even though they can arise in the absence 

of a CBA. Hawaiian Airlines, 512 U.S. at 261–62; Andrews v. Louisville & Nashville R. 

Co., 406 U.S. 320, 323–24 (1972). That Title VII is a federal statute makes no difference.

For the Court has stated that the RLA’s preemption inquiry for state claims and its

preclusion inquiry for federal claims are founded upon common “principles.” Hawaiian 

Airlines, 512 U.S. at 259 n.6. Whether in the preemption or preclusion context, “Congress 

considered it essential to keep [minor] disputes within the Adjustment Board and out of the 

courts.” Atchison, Topeka & Santa Fe Ry. Co. v. Buell, 480 U.S. 557, 562 n.9. (1987).

Following the Supreme Court’s guidance, we recently stated that a “federal claim” 

can double as a minor dispute—and thus be subject to RLA preclusion. Giles v. Nat’l R.R. 

Passenger Corp., 59 F.4th 696, 703 (4th Cir. 2023). Our sister circuits have largely agreed 

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when confronted with a smattering of nominally independent federal causes of action.

E.g., Carmona v. Sw. Airlines Co., 536 F.3d 344, 349 (5th Cir. 2008) (Title VII); Brown v. 

Illinois Cent. R.R. Co., 254 F.3d 654, 668 (7th Cir. 2001) (Americans with Disabilities 

Act); Schiltz v. Burlington N. R.R., 115 F.3d 1407, 1415 (8th Cir. 1997)

(Age Discrimination in Employment Act). The lesson from these cases is not that a federal 

claim will always be a minor dispute, but that, contrary to Polk’s view, a federal claim can

at times be one.

There is good reason not to carve out federal claims from the RLA’s preclusive 

scope. Congress understood minor disputes—that is, disagreements over the 

“interpretation or application” of a CBA—to be destabilizing in and of themselves.

Hawaiian Airlines, 512 U.S. at 252 (quoting 45 U.S.C. § 151a). The adjudication of minor 

disputes can determine prevailing CBA interpretations and therefore “govern future 

relations” between unions and carriers. Slocum v. Delaware, L. & W.R. Co., 339 U.S. 239, 

242 (1950). As a result, minor disputes have “long been considered a potent cause of 

friction leading to strikes.” Id. By getting courts out of the business of interpreting CBAs, 

Congress sought to avoid “protracted railway labor disputes” that would adversely affect 

the national economy. Fairbairn v. United Air Lines, Inc., 250 F.3d 237, 241 (4th Cir. 

2001).

The RLA’s rationale has little to do with whether a minor dispute arises from a 

contractual claim or some other cause of action under state or federal law. The end-result 

is the same: A minor dispute can be destabilizing because of its precedential implications 

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for a CBA. To mitigate that inherent risk, Congress opted for the centralized arbitration of 

minor disputes over their sporadic litigation all across the country. 

This congressional decision was premised on the several advantages that adjustment 

boards have over courts. First, their members are “peculiarly competent” in that they 

“understand railroad problems and speak the railroad jargon.” Slocum, 339 U.S. at 243–44.

Second, centralization fosters “a desirable degree of uniformity” in CBA interpretations.

Id. And third, the flexibility of arbitral procedure allows for greater delicacy and dispatch, 

reducing the likelihood of “strikes bringing railroads to a halt.” Nat’l Union Pac. R. Co. v. 

Bhd. of Locomotive Engineers & Trainmen Gen. Comm. of Adjustment, Cent. Region, 

558 U.S. 67, 72 (2009). 

Congress is, of course, welcome to pare back the RLA’s “mandatory arbitral 

mechanism.” Hawaiian Airlines, 512 U.S. at 252. But Title VII, the statute invoked by 

Polk, gives no indication that Congress meant to do that. The text of Title VII does not 

refer to, let alone repudiate, the RLA’s “elaborate administrative procedures” for minor

disputes. Buell, 480 U.S. at 562. And the broad reach of Title VII cautions against 

displacing other statutory procedures that are focused on a narrow problem. Title VII 

governs almost any entity country-wide “engaged in an industry affecting commerce” so 

long as it has fifteen or more employees. 42 U.S.C. § 2000e(b). In contrast, the RLA 

concerns itself with railroad companies and airlines. 45 U.S.C. § 151. As the “more specific 

statute,” the RLA is therefore to “be given precedence over a more general one.” Busic v. 

United States, 446 U.S. 398, 406 (1980). 

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In sum, we decline to unwind a nearly century-old statutory scheme without a clear 

congressional directive to do so. The mere fact that Polk’s claim arises under Title VII does 

not disqualify that claim from being a minor dispute within the RLA’s ambit.

2.

Polk protests that arbitration would render her Title VII rights “ineffective.”

Appellant Opening Br. at 4. But arbitration is no death knell. In extending an arbitral forum, 

the RLA serves not to deny Polk due process but to afford it.

Polk’s skepticism of arbitration is, in any event, out of step with the views of 

Congress and the Supreme Court. The Supreme Court has discussed the benefits of 

arbitration in recent years within the context of the Federal Arbitration Act (FAA), 9 U.S.C. 

§ 1 et seq. Congress’s view, the Court explained, is that arbitration can offer “quicker, 

more informal, and often cheaper resolutions for everyone involved.” Epic Sys. Corp. v. 

Lewis, 138 S. Ct. 1612, 1621 (2018). In a string of recent cases, the Supreme Court has 

rejected state- and court-made exceptions to the FAA’s strong presumption of arbitrability. 

Viking River Cruises, Inc. v. Moriana, 142 S. Ct. 1906, 1924 (2022); Epic, 138 S. Ct. at 

1619; Am. Exp. Co. v. Italian Colors Rest., 570 U.S. 228, 239 (2013); AT&T Mobility LLC 

v. Concepcion, 563 U.S. 333, 352 (2011). Under the Supreme Court’s jurisprudence, there 

is no reason to fear that arbitration will not give “statutory antidiscrimination rights the full 

protection they are due.” Penn Plaza LLC v. Pyett, 556 U.S. 247, 265 n.5 (2009).

Polk appeals to Alexander v. Gardner-Denver Co., 415 U.S. 36 (1974), but the 

Supreme Court has substantially narrowed and explicitly repudiated that decision. See 

Gilmer v. Interstate/Johnson Lane Corp., 500 U.S. 20, 35 (1991); Penn Plaza, 556 U.S. 

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at 265. The value of arbitration does not vanish simply because Polk raises a workplace 

discrimination claim. Polk’s argument about the inefficacy of arbitration is but a riptide to 

the Supreme Court’s admonition that “the advantages of the arbitration process [do not] 

somehow disappear when transferred to the employment context.” Circuit City Stores, Inc. 

v. Adams, 532 U.S. 105, 123 (2001). 

While arbitration does not compromise Title VII protections, Polk’s proposed rule 

would scuttle the RLA’s continued operation. Any dispute about a disciplinary action can 

be reframed through artful pleading as a discrimination claim under Title VII. Thus, if

Title VII claims are never minor disputes, workers will be able to “cavalierly bypass” the 

regular grievance process and arbitration and head straight to federal court merely by 

adding allegations of discrimination to a complaint. Zombro v. Baltimore City Police Dep’t, 

868 F.2d 1364, 1367 (4th Cir. 1989). This maneuver would not be difficult. But it would 

turn courts into adjudicators of first instance, whereas the RLA permits them to reverse 

adjustment board decisions only for lack of jurisdiction, failure to comply with RLA 

requirements, or taint of fraud or corruption. 45 U.S.C. § 153 (first). By blessing Polk’s 

new strategy of artful bypass, we would be nullifying the RLA’s emphatic preference for 

the arbitration of minor disputes. 

The less disruptive alternative is for claims like Polk’s to go to arbitration. Polk has

already taken the first step by filing a grievance with Amtrak’s dispute resolution office.

She can ultimately make her case to an adjustment board, half composed of union 

representatives. 45 U.S.C. § 153. In addition, Amtrak has represented that Polk can raise 

her Title VII claim and obtain Title VII relief in the arbitral forum. Oral Arg. at 19:43.

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Preclusion of a Title VII suit need not be the end of the story. Employees can still 

hold their carrier accountable for discriminatory conduct. The RLA charts the path to do

so through arbitration. 

B.

That Title VII claims can be RLA minor disputes does not end our analysis, since 

Polk also argues that at least her particular claim is not a minor dispute. As noted above, 

minor disputes “grow[] out of . . . the interpretation or application” of a CBA. Hawaiian 

Airlines, 512 U.S. at 252 (quoting 45 U.S.C. § 151a). Polk contends that her claim is not a 

minor dispute because the claim is limited to “Amtrak’s discriminatory behavior and not 

the collective bargaining agreement itself.” Appellant Opening Br. at 4. 

We disagree. The thrust of Polk’s Title VII claim is that Amtrak deviated from its 

policies when dealing with her. While Polk’s allegations as to her own treatment are 

factual, those concerning Amtrak’s policies directly implicate the relevant CBA between 

Polk’s union, SMART, and Amtrak. That some of Polk’s interpretive disagreements 

concern the Drug-Free Program does not alter the character of her claim because the 

Program is itself integrated with the CBA. Since Polk’s Title VII claim requires the 

interpretation of a CBA, it is a minor dispute. 

1.

The dispositive role of the CBA is illuminated by the substance of Polk’s Title VII 

claim. A worker may prove a claim of racial discrimination under Title VII either through 

“direct” or “circumstantial” evidence. U.S. Postal Serv. Bd. of Governors v. Aikens, 

460 U.S. 711, 714 n.3 (1983). Polk does not refer to her race or the race of her colleagues 

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in her complaint, apart from a conclusory statement that she was “discriminated against 

due to [her] race.” J.A. 14. Her allegations of racial discrimination are “circumstantial.” 

Aikens, 460 U.S. at 714 n.3.

To make out a prima facie case of Title VII discrimination in the absence of “direct 

evidence,” Polk must show “(1) membership in a protected class; (2) satisfactory job 

performance; (3) adverse employment action; and (4) different treatment from similarly 

situated employees outside the protected class.” Coleman v. Md. Ct. of Appeals, 626 F.3d 

187, 190 (4th Cir. 2010). As Polk herself appreciates, her claim thus necessitates a showing

that she was “treated differently” than other Amtrak employees on account of her race.

Appellant Opening Br. at 3. The concept of differential treatment, after all, implies a 

difference.

The problem for Polk is that evaluating her theory of differential treatment would 

require a court to interpret CBA provisions covering employee discipline and 

reinstatement. That is, Polk relies on her interpretation of these provisions as a stand-in for 

allegations about Amtrak’s factual treatment of her similarly situated colleagues. She 

chiefly alleges that Amtrak broke its own rules when it (1) terminated her for failing to 

complete the initial drug test, and then (2) tested her “excessively” beyond the one-year 

period specified in the Waiver. J.A. 15, 25. Yet even assuming arguendo that these

allegations could establish the element of differential treatment in a Title VII claim, they 

would still necessitate the “interpretation or application” of a CBA. Hawaiian Airlines, 

512 U.S. at 252 (quoting 45 U.S.C. § 151a). Polk’s claim is accordingly a minor dispute. 

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To begin, Polk contends that Amtrak’s “policy” was to give workers who failed to 

complete a drug test a second chance, not to terminate them. J.A. 25. To determine whether 

Polk is correct, a court would need to examine the CBA because the Drug-Free Program 

explicitly delegates discipline for union employees to the “appropriate collective 

bargaining agreement.” J.A. 320. In particular, Rule 25 of the CBA governs disciplinary 

measures. That provision spells out when and how Amtrak may discipline SMART 

members. It also describes what kind of offense would warrant taking an employee “out of 

service pending a trial and decision,” as Polk was. J.A. 292. A court would have to construe

Rule 25 to decide whether Amtrak strayed from its “policy” in disciplining Polk.

Polk maintains that Rule 25 does not cover her mere failure to complete a drug test. 

But her disagreement over the rule’s proper “interpretation or application” is precisely the 

kind of minor dispute that the RLA reserves for adjustment boards. Hawaiian Airlines, 

512 U.S. at 252 (quoting 45 U.S.C. § 151a). Absent examination of the CBA, it is 

impossible to say whether Amtrak’s decision to terminate Polk was standard or an 

aberration.

Polk’s second concern, related to the frequency of her drug tests, likewise hinges on

the CBA. Her objection primarily concerns the seven drug tests she received after the 

twelve-month period mentioned in the Waiver. Polk’s position is that other employees in 

her position were not tested so frequently under Amtrak’s policy, and that she has therefore 

shown differential treatment.

But Polk was not a regular Amtrak employee for drug testing purposes during the 

relevant time period. She had already been terminated and reinstated for a Drug-Free 

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Program violation, which she admitted to as part of the Waiver. J.A. 55. For some 

employees, only the Drug-Free Program might have been relevant to determining Amtrak’s 

policy for testing frequency. But for those in Polk’s situation, the corresponding policy 

implicates not only the Program but also the CBA provisions that govern employee

reinstatement. 

Two CBA provisions, in particular, are critical to interpreting Amtrak’s policy. 

Namely the “Rule G Bypass Agreement” and the “Prevention Program Companion 

Agreement” set forth reinstatement conditions for a worker following a drug violation. 

These provisions provide for “testing . . . for up to two years” and a “probationary basis 

for . . . two years” with “periodic alcohol and/or drug tests.” J.A. 298, 300 (emphasis 

added). These two-year provisions could entirely account for Amtrak’s allegedly excessive

testing of Polk, which took place in the two years after her reinstatement. Whether these 

provisions applied to Polk and how they are to be reconciled with the one-year period

mentioned in the Waiver are questions of CBA “interpretation or application” that 

constitute an RLA minor dispute. Hawaiian Airlines, 512 U.S. at 252 (quoting 45 U.S.C. 

§ 151a).

2.

Polk tries to distance her interpretative assumptions from the CBA by isolating them 

within the Drug-Free Program. But, as an initial matter, the Drug-Free Program cannot be 

so cleanly removed from the CBA. To do so would divorce Polk’s violation from Amtrak’s 

remedy. Yet Polk’s “refusal to test” under the Program would mean little detached from 

Amtrak’s disciplinary action that resulted from it. Likewise, an understanding of the

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Program’s random testing policy would be incomplete without consideration of the CBA’s

reinstatement provisions that explicitly refer to drug testing. That clear lines between the 

CBA and Program are difficult to draw is typified by the Waiver, which led to Polk’s 

reinstatement. Although Polk depicts the Waiver as a private agreement between her and 

Amtrak, it referenced the CBA and was addressed to and signed by Polk’s union 

representative.

The separation Polk seeks further overlooks the fact that the CBA incorporates the 

Drug-Free Program. CBAs are not limited to their express terms. For a CBA is “not an 

ordinary contract,” but a “generalized code to govern a myriad of cases which the 

draftsmen cannot wholly anticipate.” Consol. Rail, 491 U.S. at 311–12 (internal quotation 

marks omitted). A CBA therefore incorporates any “practice, usage and custom” which has 

been “acquiesced in by the [u]nion.” Id. (internal quotation marks omitted); see also Fry v. 

Airline Pilots Ass’n, Int’l, 88 F.3d 831, 836 (10th Cir. 1996) (noting that CBAs may 

“implicate practices, procedures, implied authority, or codes of conduct that are part of the 

working relationship”).

The Drug-Free Program encompasses an ensemble of practices and customs that 

became de facto working conditions for SMART members such as Polk. The latest version 

of the Program had been in effect since June 2017—almost two years before Polk’s initial 

test. Its policies were no secret. In Polk’s words, the Program was carried out with respect 

to “all Amtrak employees, contractors, volunteers, and applicants who have received a 

conditional offer of employment.” Appellant Opening Br. at 11. Amtrak’s actions would 

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almost inescapably be measured by its fidelity to or departure from the CBA and DrugFree Program.

Polk provides no basis to believe that her union was unaware of or hostile to the 

Program’s years-old policies. If anything, the fact that the CBA and Drug-Free Program 

cross-reference each other suggests that SMART knew of the Program and had negotiated 

suitable accommodations for its members. 

This conclusion comports with the rationale for collective bargaining. A CBA

“covers the whole employment relationship,” Steelworkers v. Warrior & Gulf Co., 

363 U.S. 574, 579 (1960), and for good reason. Workers support unions in the hopes of 

obtaining firm rights and protections. Unions and carriers devote substantial time and 

energy to negotiating comprehensive, amenable accords. The resulting CBAs are not meant 

to be brittle arrangements that labor or management can sidestep on a whim. The whole 

point is for CBA procedures to be put to workplace use. That really is all this case is about.

IV.

Based on the terms of the CBA, “the gravamen” of Polk’s Title VII claim is that 

Amtrak “violated the CBA or improperly applied it.” Giles, 59 F.4th at 703. She has 

therefore raised a minor dispute. To prevent minor disputes from becoming major ones, we 

hold that Polk’s Title VII claim is subject to arbitration under the RLA. Polk does not 

challenge the other parts of the district court’s holding on appeal, and we see no reason to 

disturb them. We therefore affirm the judgment of the district court.

AFFIRMED

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