RECOMMENDED FOR PUBLICATION
                                Pursuant to Sixth Circuit I.O.P. 32.1(b)
                                       File Name: 24a0002p.06

                    UNITED STATES COURT OF APPEALS
                                  FOR THE SIXTH CIRCUIT



                                                             ┐
  JOSEPH BRENT MATTINGLY,
                                                             │
                                   Plaintiff-Appellant,      │
                                                             │
         v.                                                   >        No. 22-5794
                                                             │
                                                             │
  R.J. CORMAN RAILROAD GROUP, LLC; R.J. CORMAN               │
  RAILROAD SERVICES, LLC; R.J. CORMAN RAILROAD               │
  COMPANY/MEMPHIS LINE aka R.J. Corman Railroad              │
  Company/Memphis Line, Inc.,                                │
                              Defendants-Appellees.          │
                                                             ┘

 Appeal from the United States District Court for the Eastern District of Kentucky at Lexington.
                    No. 5:19-cv-00170—Joseph M. Hood, District Judge.

                                     Argued: July 27, 2023

                              Decided and Filed: January 3, 2024

                                       _________________

                                            COUNSEL

ARGUED: Joseph H. Mattingly III, JOSEPH H. MATTINGLY III, PLLC, Lebanon, Kentucky,
for Appellant. James T. Blaine Lewis, MCBRAYER PLLC, Louisville, Kentucky, for Appellees.
ON BRIEF: Joseph H. Mattingly III, JOSEPH H. MATTINGLY III, PLLC, Lebanon, Kentucky,
William C. Robinson, Elizabeth Graves Coulter, MATTINGLY, SIMMS, ROBINSON &
MCCAIN, PLLC, Springfield, Kentucky, for Appellant. James T. Blaine Lewis, Shane O’Bryan,
MCBRAYER PLLC, Louisville, Kentucky, for Appellees.
                                      _________________

OPINION

                                      _________________

       STEPHANIE D. DAVIS, Circuit Judge. While employed by R.J. Corman Railroad
Services, LLC (“Corman Services”), Plaintiff-Appellant Joseph Brent Mattingly sustained injuries
  No. 22-5794              Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 2


during the repair of a bridge owned and operated by a common carrier, Defendant-Appellee
Memphis Line Railroad (“Memphis Line”). Mattingly filed suit to recover damages under the
Federal Employers’ Liability Act (“FELA”), 

. The district court determined that
Mattingly was not employed by a common carrier—a prerequisite to trigger FELA liability—and
granted Defendants’ Motion for Summary Judgment. Mattingly challenges that ruling as well as
the district court’s entry of summary judgment before ruling on an important discovery dispute.
Specifically, Mattingly faults the district court for not allowing individualized discovery as to
Memphis Line after its late addition as a party. Because we conclude that Mattingly was not
employed by a common carrier and is thus not entitled to FELA coverage, we AFFIRM.

                                                I.

                                               A.

       Defendants in this case are individual members of a corporate family. Defendant R.J.
Corman Railroad Group, LLC (“Corman Group”) is the holding company for, and sole Member
and Manager of, various subsidiary companies including Corman Services—a construction
company that performs repair and construction work on railroad tracks and bridges throughout the
country—and R.J. Corman Railroad Company, LLC (“Railroad Company”). Railroad Company,
although not a party to this case, owns various short-line railroads, including Memphis Line.

       In January 2017, Mattingly fell while performing bridge repair work on the Memphis Line
and sustained several serious injuries, which ultimately led to the amputation of his left leg. At
the time of the accident, Mattingly was nominally employed by Corman Services.

       Memphis Line Project. Memphis Line retained Corman Services to repair the Red River
Bridge and the Cumberland River Bridge (collectively, the “Memphis Line Project”) in
Clarksville, Tennessee. Mattingly supervised his own bridge repair crew solely comprised of
Corman Services employees on the Memphis Line Project. Mattingly assigned crew members to
equipment, assured that they had all necessary tools, and picked the spot they would work on each
day. He reported to the superintendent, Paul Childres, another Corman Services employee who
also supervised a separate crew of Corman Services bridge workers. Mattingly and Childres both
reported to a Corman Services operations manager. Initially, the entire Corman Services team
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 3


reported to the Cumberland River Bridge, but Memphis Line later determined it would be more
efficient to divide the workflow between the two bridges. Mattingly and his crew therefore
switched to the Red River Bridge, and Childres and his crew remained at the Cumberland River
Bridge approximately two miles away.

       In addition to Corman Services employees, Railroad Company employees were involved
in the Project. Jason Topolski, a Railroad Company bridge inspector who was on Memphis Line’s
payroll, was present at the job site. As bridge inspector, Topolski was responsible for ensuring the
safety of Railroad Company bridges, which included ensuring the satisfactory maintenance and
repair of those bridges. Cain Jones, another Railroad Company worker, was also present on the
job site and served as its joint “Employee in Charge” alongside Topolski. Federal regulations
mandate the appointment of an Employee in Charge on railway projects.               See 

; 214.319; 214.353. The role involves ensuring railroad workers’ safety on the tracks,
including by communicating with dispatch to monitor train traffic passing through the job site and
stopping work, if necessary, to allow the trains to pass.

       Either Topolski or Jones was physically present onsite throughout the Memphis Line
Project. At the outset of the Project, Memphis Line provided Corman Services with a list of bridge
posts in need of repair, and Mattingly marked these posts. Mattingly and his crew worked to
replace posts, caps, and cross braces on the bridge. At times, Memphis Line would adjust the
priority or timing of repairs based on anticipated train traffic. Mattingly testified that Topolski
would show employees how to complete discrete tasks, such as how to drill a hole. That said,
Topolski mostly instructed the railroad’s newer employees and generally stayed out of Mattingly’s
way since Mattingly was more familiar with bridge work than others.

       Though Mattingly placed Topolski at the worksite “the whole time [Mattingly] was there,”
(R. 62-4, PageID 963), Topolski estimated that he was present at the Memphis Line Project site
two to three days a week and not for the entire day. He admitted that he sometimes advised Corman
Services’ employees on certain matters and communicated with them about what the railroad
needed done. Nevertheless, Topolski maintained that he did not supervise the Corman Services
workers or otherwise tell the railroad crews what to do each day. He explained that if he did
perform work on the Project, it would have been tasks outside of Corman Services’ scope of work.
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 4


       One of Mattingly’s crew members, Dillon Neace, testified that Topolski may have been on
the Cumberland River Bridge when the Memphis Line Project first started, but otherwise was not
present at the job site. Neace apparently did not view Topolski’s directions as requirements to
follow. Rather, he stated that he would “probably listen” to Topolski if he told him to do something
on the project because of Topolski’s greater knowledge about bridge work and not due to his status.
(R. 62-15, PageID 2048–49). Neace also explained that if Jones asked him to do something
pertaining to the Memphis Lines Project, he would first check with Mattingly and Childres.
Michael Wilson, another member of Mattingly’s crew at Red River, testified that he rarely saw
Topolski or Jones.

       At the start of every day, two safety meetings would take place on the Memphis Line
Project—one typically led by Memphis Line regarding track protection, and one led separately by
and for Corman Services employees. As a supervisor, Mattingly was required to provide daily
production reports to Memphis Line to apprise them of the project’s progress. This practice was
common, regardless of whether Corman Services was working for a Corman Railroad Company
railroad or for a non-Cormon-owned line. At the time of Mattingly’s accident, only Corman
Services employees were present at the Red River Bridge; Jones was on the Cumberland River
Bridge and Topolski was on a separate project out-of-state. Mattingly testified that he was his own
supervisor at that point in time.

       Corporate Organization. Corman Group provides administrative services to its subsidiary
companies, including payroll, accounting, legal, human resources, information technology, public
affairs, private aircraft services, risk management, purchasing, and commercial development. It
maintains several joint policies that apply to all its subsidiaries, including single workers’
compensation; general liability insurance; automobile liability and life insurance policies; along
with joint health insurance benefits and a single retirement plan. It charges each individual
company a monthly fee for its services. Leaders of Corman Group’s subsidiaries are considered
senior staff and report directly to Corman Group’s President, Ed Quinn. Corman Group also
created and memorialized Senior Staff Policies. However, Corman Group maintains that they
were “legacy documents,” and that Quinn was unaware of their existence and did not adhere to the
policies. (R. 79-2, PageID 3414, ¶¶ 15–16). Corman Group also has developed safety protocols
  No. 22-5794              Mattingly v. R.J. Corman R.R. Grp., LLC                         Page 5


applicable to all its subsidiaries and conducts annual mandatory safety trainings for all subsidiary
employees. Further, Quinn approves the annual budget of each subsidiary as well as purchases
over a certain amount.

       Each of Corman Group’s subsidiaries, including Corman Services, employs a president, a
vice president, managers, and supervisors separate from Corman Group. Corman Services makes
its own hiring, firing, promotion, and disciplinary decisions. It also independently manages its
employees’ schedules. Corman Services’ largest customers include Class I railroads, as well as
short line and regional railroads unaffiliated with the Railroad Company railroads. Railroad
Company routinely solicits bids from other repair and construction companies, but frequently
chooses Corman Services for work when availability permits. When Corman Services works on
one of Railroad Company’s railroads, including Memphis Line, it charges only the actual cost for
labor and equipment, not the market rate. Undisputed testimony indicates that whether and for
how long Corman Services remains on a Railroad Company job is directly related to whether
Corman Services has any non-Corman work. The record also shows that Corman Services often
left Railroad Company jobs before completion. In Topolski’s experience, Corman Services
prematurely pulled out of every Railroad Company job that had ever been assigned to it, without
consequence.

                                                B.

       Mattingly filed a complaint in the United States District Court for the Eastern District of
Kentucky, initially naming Corman Group and Corman Services as defendants. Mattingly sought
compensation under FELA for his injuries and losses. The district court ordered phased discovery,
allowing first for discovery on the threshold issue of FELA applicability. Once discovery and
dispositive motions regarding the Act’s applicability were complete, the court would set the second
phase of discovery as needed. During phase I discovery, the magistrate judge denied Mattingly’s
request to obtain a copy of Corman Group’s consolidated external audit report. Mattingly filed a
motion for modification of the magistrate judge’s order, which the magistrate judge denied.
Mattingly filed objections to the magistrate’s order that remained unresolved when summary
judgment was issued.
  No. 22-5794              Mattingly v. R.J. Corman R.R. Grp., LLC                         Page 6


       As the case progressed, the court granted Mattingly’s motion for leave to file a second
amended complaint in which he sought to add Memphis Line as a defendant over Defendants’
objections. Several months later, Memphis Line was added as a defendant in the Second Amended
Complaint.

       Discovery closed on the FELA applicability issue. Mattingly moved for partial summary
judgment as to that issue, and Corman Group and Corman Services moved for summary judgment
as to Mattingly’s FELA claims. For his part, Mattingly asserted that under the “unitary theory,”
Corman Group operated its subsidiaries as an organized, unitary railroad system, rendering
Corman Group and all of its subsidiaries—including Corman Services—common carriers for the
purposes of FELA. Alternatively, he argued that he should be considered the employee of a
common carrier for purposes of FELA based on common-law principles, as a subservant of a
company (Corman Services) that was in turn acting as a servant of a common carrier (Corman
Group and Memphis Line).

       In August 2022, the district court determined that FELA does not apply to Mattingly’s
claim and granted Defendants’ motion for summary judgment, including all claims against the
later-added defendant, Memphis Line. It did so without ruling on Mattingly’s pending discovery
objections, and without reopening discovery to allow for a targeted inquiry as to Memphis Line.
In granting summary judgment, the court reasoned that Mattingly’s unitary theory for recovery
was not supported by law, and that he had failed to present adequate evidence from which a rational
jury could find that Memphis Line controlled, or had the right to control, Corman Services or
Mattingly’s daily work at the time of his injury under common-law principles. This appeal
followed.

                                                II.

       We review the district court’s grant of summary judgment de novo. See Kentucky v. Yellen,

 (6th Cir. 2022). In doing so, the court must view the facts in the light most
favorable to Mattingly as the non-moving party and give him the benefit of all reasonable
inferences arising from the record. See LaPlante v. City of Battle Creek, 

 (6th
Cir. 2022). Summary judgment is appropriate where the movant shows that there exists no genuine
  No. 22-5794                 Mattingly v. R.J. Corman R.R. Grp., LLC                            Page 7


dispute of material fact, and the movant is entitled to judgment as a matter of law. See Fed. R.
Civ. P. 56. We review the district court’s rulings regarding discovery under a highly deferential
abuse-of-discretion standard. See Blount v. Stanley Eng’g Fastening, 

 (6th Cir.
2022).

                                                   III.

                                                    A.

         FELA Applicability. Mattingly maintains that the district court erred in concluding that
Corman Services is not a common carrier, and as such, FELA coverage does not extend to
Mattingly. FELA provides the exclusive remedy for employees of common carriers by railroad to
recover damages for injuries sustained during the course of employment. The statute provides that
a common carrier by railroad engaging in commerce:

         shall be liable in damages to any person suffering injury while he is employed by
         such carrier in such commerce . . . for such injury or death resulting in whole or in
         part from the negligence of any of the officers, agents, or employees of such carrier,
         or by reason of any defect or insufficiency, due to its negligence, in its cars, engines,
         appliances, machinery . . . or other equipment.

. Relevant here, FELA applies only to (1) employees (2) of a common carrier by
railroad.

         On appeal, Mattingly advances the same two theories for FELA coverage that he did in the
district court: unitary theory and subservant liability. But neither theory supports Mattingly’s
claim for recovery. We address each in turn.

         1. Unitary Theory

         Mattingly first asserts that Corman Group’s ownership, management, and control over
Corman Services and its common carrier subsidiaries makes Corman Services a member of a
“unitary” railroad system and, consequently, a common carrier for purposes of FELA. This
argument, however, essentially asks the court to disregard Defendants’ corporate structure to hold
Corman Group and its non-common carrier subsidiaries (including Corman Services) liable under
FELA. This we cannot do.
  No. 22-5794              Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 8


       The Supreme Court has interpreted FELA’s use of “common carrier by railroad” to mean
“one who operates a railroad as a means of carrying for the public—that is to say, a railroad
company acting as a common carrier.” Wells Fargo & Co. v. Taylor, 

 (1920).
More recently, we have elaborated that a “common carrier” under FELA is:

       one who holds himself out to the public as engaged in the business of transportation
       of persons or property from place to place for compensation, offering his services
       to the public generally. The distinctive characteristic of a common carrier is that
       he undertakes to carry for all people indifferently, and hence is regarded in some
       respects as a public serv[a]nt.

Kieronski v. Wyandotte Terminal R.R. Co., 

 (6th Cir. 1986) (citation omitted).
FELA also includes in its definition of a common carrier, “persons or corporations charged with
the duty of the management and operation of the business of a common carrier.” 

.

       Mattingly’s unitary theory relies on two early-twentieth-century Supreme Court cases:
Southern Pacific Terminal Co. v. Interstate Com. Comm’n, 

 (1911) and United States
v. Union Stockyards & Transit Co. of Chi., 

 (1912). In both cases, the Court weighed
whether entities held in common ownership alongside common carriers might be deemed common
carriers for purposes of the Interstate Commerce Act of 1887, 

 Stat. 379,
and whether they were within the jurisdiction of the Interstate Commerce Commission (“ICC”).
These cases carry some limitations in the context of Mattingly’s FELA claims, but they are useful
in providing general principles for our analysis. See Kieronski, 

 (examining
Southern Pac. Terminal Co. and Union Stockyards applicability to FELA claims).

       Southern Pacific appears to provide the Court’s earliest guidance on the unitary theory. In
that case, the Supreme Court found that Southern Pacific Terminal (“SP Terminal”)—a business
entity owned by Southern Pacific Company, which in turn owned a group of individually
incorporated railroads—was a common carrier. Id. at 517. SP Terminal was in the business of
operating wharves and docks to accommodate the import and export of freight. Id. at 502. The
wharves and docks themselves were connected to the railroad tracks of SP Terminal’s sister
companies. Id. at 503. The Court concluded that SP Terminal was a common carrier, in part,
because of its ownership and operation, along with its sister companies, by a single corporation.
In that regard, the Court noted the fact that Southern Pacific Company “control[led] . . . the
  No. 22-5794                Mattingly v. R.J. Corman R.R. Grp., LLC                            Page 9


properties . . . through stock ownership.” Id. at 521 (“There is a separation of the companies if we
regard only their charters; there is a union of them if we regard their control and operation through
the Southern Pacific Company.”). Equally important, SP Terminal “form[ed] a link in the chain
of transportation” for the respective companies. Id. at 522. That is to say, SP Terminal’s wharves
and docks were “necessary to complete the avenue through which move shipments over [the] lines
owned by a single corporation,” making SP Terminal a common carrier for purposes of ICC
jurisdiction. Id. (emphasis added).

        In Union Stockyards, the Court similarly found that the defendant, “Stock Yard Company,”
was a common carrier subject to the Interstate Commerce Act. 

. The Stock Yard
Company was held by a parent company, and that parent company also held Junction Company—
an owner and operator of railroads. 

 The Stock Yard Company operated facilities to load and
care for livestock in their journey over Junction Company’s rail lines. It also received two-thirds
of Junction Company’s profits. 

. Again, while the fact that Stock Yard Company and
Junction Company shared a common owner was a relevant consideration in the Court’s holding,
the salient consideration was that Stock Yard Company’s facilities and services provided a
necessary physical link in the chain of interstate commerce. 

 at 304–05. Moreover, the character
of the services rendered by Stock Yard Company were that of a common carrier because it
“perform[ed] services as a railroad.” 

 (“Together, these companies, as to freight which is being
carried in interstate commerce, engage in transportation within the meaning of the act, and perform
services as a railroad when they take the freight delivered at the stock yards, load it upon cars, and
transport it for a substantial distance upon its journey in interstate commerce . . . or receive it while
it is still in progress in interstate commerce.”).

        Here, Corman Services’ bridge repair and construction services do not provide such an
inextricable function for Memphis Line’s common carrier services like the entities in Southern
Pacific Terminal and Union Stock Yard did. Granted, the maintenance and repair of railroad tracks
and bridges is surely integral to the operation of railroads. But maintenance is not a rail service
contracted for by the public when it engages Memphis Line as a common carrier. In the leading
cases, the plaintiffs functioned to actively keep things—freight and livestock respectively—
moving in interstate commerce. In this case, Corman Services maintained the physical structure
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 10


of the railroad, but it was not an active participant in the chain of commerce itself. See Union
Stockyards, 

 (emphasizing that the primary consideration is whether the “service
to be performed was a part of the carriage of freight by railroad in interstate commerce”) (citing
Southern Pacific, 

); see also Kieronski, 

 (understanding Southern Pac.
Terminal and Union Stockyards to extend common carrier liability to “linking” entities that have
“common ownership” with a railroad).

       Edwards v. Pacific Fruit Express Company offers additional guidance. 

(1968). In Edwards, the Supreme Court addressed Congress’s reluctance to expand the meaning
of common carriers in its 1939 amendments to FELA. The Court observed that “[b]y refusing to
broaden the meaning of railroads, Congress declined to extend the coverage of the Act to activities
and facilities intimately associated with the business of common carrier by railroad.” 

.
While the Edwards Court weighed whether renting refrigerator cars to railroads and providing
protective services in the transport of perishable commodities constituted the business of a
common carrier, the Court’s logic that, “while used in conjunction with railroads and closely
related to railroading, are yet not railroading itself,” applies with equal heft to Corman Services’
construction and repair activities. 

.

       Moreover, an age-old principle of corporate common-law “deeply ‘ingrained in our
economic and legal systems’” is useful to our analysis as well: “a parent corporation . . . is not
liable for the acts of its subsidiaries.” United States v. Bestfoods, 

 (1998) (quoting
William O. Douglas & Carrol M. Shanks, Insulation from Liability Through Subsidiary
Corporations, 

, 193 (1929)); see also Schultz v. Gen. Elec. Healthcare Fin. Servs.,

 (Ky. 2012) (“General principles of corporate law, specifically with respect
to piercing the corporate veil, have become axiomatic. For example, it is widely accepted that a
corporation should be viewed as a separate legal entity.”).           Mattingly does not present
circumstances warranting the disregard of Defendants’ separate corporate structure.

       For instance, in Bestfoods, the Supreme Court considered whether a parent corporation
could be charged with derivative liability for its subsidiary’s actions under the Comprehensive
Environmental Response, Compensation and Liability Act (“CERCLA”). In answering in the
negative, the Court looked to the statute itself. It emphasized that CERCLA was notably silent on
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                         Page 11


“the liability implications of corporate ownership.”        Id. at 63.   And the statute’s silence
“demand[ed] application of the rule that, to abrogate a common-law principle, a statute must speak
directly to the question addressed by the common law.” Id. (citing United States v. Texas, 

 (1993)). The Court’s guidance in Bestfoods leads us down two paths—statutory and
common law—both yielding the same result.

       First, unlike CERCLA, FELA arguably does contemplate a circumstance in which courts
may disregard separate corporate entities. See 45 U.S.C § 55. Section 55 voids “[a]ny contract,
rule, regulation, or device whatsoever,” with “the purpose or intent . . . to enable any common
carrier to exempt itself from any liability created” by FELA. At least one of our sister circuits has
interpreted the provisions of Section 55 to “encode[] the [corporate] ‘domination’ doctrine to the
extent the FELA permits the use of this doctrine to pierce the corporate veil.” See Selser v. Pac.
Motor Trucking Co., 

 (5th Cir. 1985). The Fifth Circuit in Selser addressed
whether a common carrier parent company could be liable under FELA for its non-common carrier
subsidiary. The court reasoned that “common law ‘domination’ is . . . relevant only to the extent
to which it may evidence intent or purpose to exempt the parent [] from FELA liability.” Id.; see
also Smith v. Rail Link, Inc., 

 (10th Cir. 2012) (noting in dicta that plaintiff
“might succeed” in implicating the corporate parent of common carrier subsidiaries as a common
carrier subsidiary itself “if she could show that this corporate structure was established as a means
of evading FELA liability”).

       Citing Petersen v. Ogden Union Ry. & Depot Co., 

 (Utah 1946),
Mattingly maintains that Corman Group’s organization has the practical effect of exempting some
of its employees from FELA liability, providing sufficient grounds to fall within the ambit of § 55.
But Petersen, a state court decision from Utah, appears to stand alone in its interpretation of the
Act. We do not take such a liberal view of FELA’s statutory language. This court’s sister
circuits—and the plain language of the statute—indicate that the purpose and intent, not the
“practical effect,” of the device in question is relevant to the analysis. See Selser, 

(“By its terms, section 55 voids all devices, and only those devices, whose actual purpose or intent
is to enable a carrier to exempt itself from liability.”) (emphasis in original); Smith, 

 (“[Plaintiff] might succeed if she could show that this corporate structure was established as
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 12


a means of evading FELA liability.”). Mattingly points to no evidence that Corman Group
designed its corporate structure with the purpose or intent to exempt itself from FELA liability.
To the contrary, undisputed record testimony reflects numerous legitimate purposes for the
corporate segregation of the companies, including their diverse functions, clientele, suppliers, and
management requirements.

       Mattingly fares no better if we instead apply corporate common-law principles as in
Bestfoods. 

; see also Willard v. Fairfield S. Co., 

 (11th Cir. 2006)
(considering Alabama corporate law to determine whether a railroad “so control[led] the operation
of [the plaintiff’s nominal employer] as to make it a mere adjunct, instrumentality, or alter ego of”
the railroad for purposes of FELA); Greene v. Long Island R.R. Co., 

 (2d Cir.
2002) (similar). State law dictates whether circumstances exist warranting piercing the corporate
veil. See Longhi v. Animal & Plant Health Inspection Serv., 

 (6th Cir. 1999).
“Under Kentucky law, separate corporate interests, including subsidiaries and affiliates . . . are
separate legal entities and must be recognized and treated as such unless there is some reason to
pierce the corporate veil.” Hazard Coal Corp. v. Ky. W. Va. Gas Co., 

 (6th Cir.
2002). And such reasons are found “only in the rarest of circumstances.” Schultz, 

. Specifically, two elements must be met: “(1) domination of the corporation resulting in a loss
of corporate separateness and (2) circumstances under which continued recognition of the
corporation would sanction fraud or promote injustice.” Howell Contractors, Inc. v. Berling,

 (Ky. Ct. App. 2012) (emphasis in original) (quoting Inter-Tel Techs., Inc. v.
Linn Station Props., LLC, 

 (Ky. 2012)). Considerations going to the first
factor include “grossly inadequate capitalization, egregious failure to observe legal formalities and
disregard of distinctions between parent and subsidiary, and a high degree of control by the parent
over the subsidiary’s operations and decisions, particularly those of a day-to-day nature.” Inter-
Tel Techs., Inc., 360 S.W.3d at 164. While Mattingly cites evidence that Corman Group exercised
some degree of control over its subsidiaries, the evidence advanced does not warrant the
exceptional measure of disregarding corporate formalities among the entities. The subsidiary
Defendants managed their own daily operations and maintained corporate officers and personnel
distinct from Corman Group; Mattingly presents no evidence that the subsidiary Defendants were
not financially independent of Corman Group; and Services maintained substantial business
  No. 22-5794                    Mattingly v. R.J. Corman R.R. Grp., LLC                                  Page 13


relationships beyond the Corman Group subsidiary railroads. Thus, a common law approach is no
more effective here than a statutory one.

         As such, Mattingly does not present a genuine dispute of material fact as to whether
Corman Services may be considered a common carrier based on its relationship to Corman Group
under FELA.

         2. Subservant Theory

         Mattingly next asserts that even if Corman Services cannot be considered a common carrier
by virtue of Corman Group’s operation, common-law employment principles still render him an
employee of Memphis Line.

         Under FELA, the words “employee” and “employed” are intended in their natural sense,
established by proof of a master-servant relationship under traditional principles of common law.
Kelley v. S. Pac. Co., 

 (1974). A master-servant relationship under common law
exists where “a person employed to perform services in the affairs of another and who with respect
to the physical conduct in the performance of the services is subject to the other’s control or right
to control.” 

 at 324 (quoting Restatement (Second) of Agency § 220(1) (1958)).

         The parties agree that the leading case on the matter is Kelley. There, the Supreme Court
enumerated three approaches for a plaintiff seeking coverage under FELA to establish common
law employment with a common carrier. Id. at 324. Mattingly chose to proceed under the
“subservant” approach, which allows him to rely on evidence that he was acting as “a subservant
of a company that was in turn a servant of the railroad.” Id. To prevail under this approach,
Mattingly must show that (1) Corman Services was a servant of Memphis Line, and (2) he was
subject to the control of both Memphis Line and Corman Services.1 Because we do not find that


         1
          In his briefs before this court, Mattingly states that both Corman Group and Memphis Line were “masters”
of Corman Services for purposes of the subservant theory. (Dkt. 22, Page 50). However, the substance of his argument
focuses solely on Memphis Line’s control over Services (see id. at 52–53; Dkt. 33, Page 21). We therefore address
only the master-servant relationship between Memphis Line and Corman Services. See Berkshire v. Dahl, 

 (6th Cir. 2019) (“[A] defendant forfeits an argument by . . . identifying it without pressing it.”) (quoting
United States v. White, 

, 1122–23 n.4 (6th Cir. 2019)). Although Mattingly’s arguments are forfeited,
Defendants directly and adequately addressed the issue in their response brief. (Dkt. 27, Page 53–54). With no counter
to the defendant’s well taken arguments, Mattingly cannot prevail on this issue.
  No. 22-5794              Mattingly v. R.J. Corman R.R. Grp., LLC                       Page 14


Memphis Line controlled or had the right to control Corman Services’ daily operations such as to
establish a master-servant relationship, Mattingly’s subservant theory of employment must fail.

       The facts of Kelley—where the Supreme Court determined that the district court’s findings
did not establish a master-servant relationship between the plaintiff’s nominal employer and a
defendant railroad company—are helpful to our review. The plaintiff was employed by a trucking
company (“PMT”) and sustained injuries while unloading vehicles from the defendant-railroad
company’s railcar to PMT’s trailer. Id. at 321. PMT was a wholly owned subsidiary of the railroad
company, and the plaintiff-employee claimed to be employed by the railroad company for
purposes of FELA. Id. The district court found that the relationship between the plaintiff-
employee and the railroad company established FELA liability. Id. The district court reasoned
that because PMT was serving as an agent of the railroad, the railroad was ultimately “responsible”
for the unloading operation; PMT employees were the railroad’s agents for purposes of the
unloading operation; and the work performed by the plaintiff fulfilled a nondelegable duty of the
railroad. Id. at 322.

       The Court of Appeals for the Ninth Circuit reversed, finding the district court’s test for
FELA liability too broad; the Supreme Court agreed. Id. The Court reasoned that FELA liability
requires more than an agency relationship, but that of a “master-servant” where the railroad must
have “controlled or had the right to control the physical conduct of PMT employees in the course
of their unloading operations.” Id. at 325. It did not matter that railroad employees were
responsible for checking safety conditions on the site—this only “reflect[ed] the fact that the
activities of the two companies were closely related and necessarily had to be coordinated.” Id. at
326–27. And despite railroad supervisory personnel being on site and occasionally advising or
consulting with PMT employees and supervisors, the railroad did not play “a significant
supervisory role in the unloading operations.” Id. at 327. Further, “[t]he two companies were
sufficiently distinct in organization and responsibility that there was no apparent overlap in the
supervisory ranks.” Id.

       Under facts similar to Mattingly’s, we applied Kelley’s subservant theory to FELA claims
in Campbell v. BNSF Railway Company, 

 (6th Cir. 2010). We found no master-
servant relationship between the plaintiff’s employer, Pacific Rail Services, LLC (“PRS”), and
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BNSF Railway Company, with whom PRS contracted. 

. The plaintiff in Campbell was
injured while driving a railroad transport vehicle at a railyard owned by BNSF. 

 BNSF
employed one worker at the terminal: a hub manager who was charged with ensuring that PRS
workers timely completed their assignments and followed BNSF’s safety protocols. 

.
The hub manager also discussed with PRS employees which tracks needed to be cleared and
spotted, but PRS managers and supervisors were otherwise responsible for directing the specifics
of PRS employees’ activities, assigning containers to rail cars, and coordinating and tracking the
work. 

 Further, BNSF had no authority to hire, train, evaluate, discipline, or terminate PRS
employees. 

. PRS maintained substantial business relationships outside of its dealings
with BNSF and had complete authority over its employees’ schedules; PRS could also assign any
number of workers to the BNSF terminal. 

 Taken together, the court found that “PRS
controlled, and had the exclusive right to control, its employees as BNSF’s independent
contractor,” and as such, the subservant theory failed. 

.

       Similarly, Mattingly does not establish that Corman Services was a conventional common-
law servant of Memphis Line. Corman Services employed its own supervisory personnel who
were present at the job site each day. See Kelley, 

. Corman Services paid its
workers from its own bank account. See 

 (considering that a nominal employer “fixed
and paid [workers’] wages”). Corman Services determined which and how many of its workers
would show up at each job, including the Memphis Line Project. See Campbell, 

.
Memphis Line had no authority to hire, fire, discipline, train, or evaluate Corman Services
employees. See 

. For example, Childres conducted Mattingly’s employee evaluations,
and Mattingly in turn conducted employee evaluations for his supervisees at Corman Services.
Moreover, Corman Services had “substantial business relationships” outside of its dealings with
Memphis Line.      

.   In fact, these external business relationships apparently took
precedence over its relationships with the Railroad Company railroads, as Corman Services often
dropped Corman jobs if other work became available. Moreover, while the railroad defined the
scope of the work on the Memphis Line Project—identifying which bridge posts required repair—
Corman Services controlled its own day-to-day schedule. See 

.
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       The relative roles of the companies are also relevant here. See e.g., Kelley, 419 U.S. at
326–27; Standard Oil Co. v Anderson, 

 (1909). Memphis Line retained
responsibility for ensuring the safety of Corman Railroad bridges and the work site, while Corman
Services was utilized to repair unsafe portions of the bridge. The Standard Oil Company decision
is instructive here. In Standard Oil Company, the Court explained that a winchman obeying the
signals of a gangman while timing the raising and lowering of cases of oil “showed co-operation
rather than subordination” and “not the [taking] of orders, but of information.” 

.
Mattingly’s version of the facts, viewed in the context of the functions of Memphis Line and
Corman Services on the Memphis Line Project are also more indicative of cooperation than
subordination, and “reflect the fact that the activities of the two companies were closely related
and necessarily had to be coordinated.” Kelley, 

; see Standard Oil Co., 

 (“[W]hen one large general work is undertaken by different persons, doing distinct parts of
the same undertaking, there must be co-operation and co-ordination, or there will be chaos.”). And
similar to Kelley, due to the nature of the work performed, the companies “naturally had substantial
contact with one another.” Kelley, 

. As such, the evidence demonstrates that
Corman Services was not subjugated to the control or right to control of Memphis Line.

       In resisting this result, Mattingly directs our attention to his testimony that Topolski was
often present at the Project, and Topolski’s testimony that he might offer advice to Corman
Services bridge crew members regarding some tasks. But even resolving the conflicting facts in
Mattingly’s favor, Topolski’s unilateral actions on the Project fall short of establishing Memphis
Line’s control over Corman Services. See Kelley, 

 (“The informal contacts between
the two groups must assume a supervisory character before the [contractor’s] employees can be
deemed pro hac vice employees of the railroad.”). Other testimony, including Mattingly’s own,
showed that Topolski’s involvement on the Project did not take on a supervisory character. See

 (railroad personnel “advis[ing] or consult[ing] with [contractor] employees and
supervisors” does not equate to a “significant supervisory role.”).       For example, Mattingly
explained that while Topolski might instruct newer employees as to certain tasks, he and Topolski
stayed out of each other’s way because he was more familiar with bridge work. And one of
Mattingly’s subordinates on the Project, Mr. Neace, explained that he would “probably listen” to
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                        Page 17


Topolski due to his knowledge and experience, but not due to his status. (R. 62-15, PageID 2048–
49).

       To the extent that Mattingly claims that Topolski “dictated the times when Corman
Services employees could work,” he also conceded that this was “in relation to when Corman
trains needed to pass.” (Dkt. 22, Page 34). Such coordination not only indicates “necessary
cooperation” as opposed to a master-servant relationship, but it is also consistent with a railroad’s
federally mandated role in ensuring the safety of on-track workers under 

,
214.319, 214.353. See, e.g., Campbell, 

 (explaining that a railroad’s obligation to
adhere to safety requirements does not demonstrate employment relationship); Royal v. Mo. & N.
Ark. R.R. Co., Inc., 

 (8th Cir. 2017) (same). Similar reasoning applies to the
requirement that Corman Services supervisors, including Mattingly, circulate daily production
reports by e-mail to Railroad Company supervisors. This practice permitted the railroad to keep
track of the work being completed and comply with federal safety requirements. Both Mattingly
and Childres testified that this was a standard practice that they would complete for any railroad
with whom Corman Services contracted.

       Ultimately, Mattingly does not present a genuine dispute of material fact regarding whether
Corman Services, as an entity, was merely a common-law servant to Memphis Line or whether
Corman Group’s operations established a unitary organization for FELA applicability.
Accordingly, we hold that the district court did not err in granting summary judgment to
Defendants on Mattingly’s FELA claim because Mattingly was not employed by a common carrier
under the Act.

                                                 B.

       Discovery Issues. Lastly, Mattingly maintains that the district court failed to (1) order
discovery as to Memphis Line once it was added as a party, and (2) resolve a pending discovery
dispute. Generally, summary judgment is improper if the non-movant is not afforded a sufficient
opportunity for discovery. See Ball v. Union Carbide Corp., 

 (6th Cir. 2004)
(citing Anderson v. Liberty Lobby, Inc., 

 (1986)).
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       Mattingly’s first claim lacks merit. In June 2021, the parties filed dispositive motions.
Memphis Line subsequently entered its appearance in December 2021. In August 2022, the district
court granted Defendants’ motion for summary judgment on the FELA claim and included
Memphis Line in the order and corresponding judgment. There is no indication that Mattingly
sought to initiate a discovery conference or sought additional discovery as to Memphis Line in the
months following its addition as a party. See Fed. R. Civ. P. 26(f)(2) (“The attorneys of
record . . . that have appeared in the case are jointly responsible for arranging the [discovery]
conference.”). Having failed to preserve the Memphis Line discovery dispute below, Mattingly
cannot challenge it here. See Stemler v. City of Florence, 

, 866 n.9 (6th Cir. 1997).
In any event, Mattingly cannot support his claim on appeal that he was not afforded a “sufficient
opportunity” for discovery as to Memphis Line. See Vance, v. United States, 

(6th Cir. 1996.)

       Mattingly’s remaining claim of error is similarly without merit. During discovery, the
magistrate judge denied Mattingly’s request to obtain a copy of Corman Group’s consolidated
external audit report, which he claims would reveal important aspects about the control that
Corman Group exercised over its subsidiaries. Mattingly filed a motion to modify the decision
and the magistrate judge denied that motion. Mattingly filed objections to the magistrate judge’s
order, but the district court never ruled on the objections. The parties subsequently filed dispositive
motions.

       In the context of a motion for summary judgment, “[t]he non-movant bears the obligation
to inform the district court of his need for discovery” by complying with Federal Rule of Civil
Procedure 56(d). 

 at 1148–49. An affidavit pursuant to Rule 56(d) “must ‘indicate to the district
court [the non-movant’s] need for discovery, what material facts it hopes to uncover, and why it
has not previously discovered the information.’” Doe v. City of Memphis, 

 (6th
Cir. 2019) (quoting Ball, 

). If a non-movant fails to comply with Rule 56(d), the
issue of whether summary judgment was prematurely entered because additional discovery was
required is not preserved for appeal. See Vance, 

; see also Plott v. Gen. Motors
Corp., Packard Elec. Div., 

 (6th Cir. 1995).
  No. 22-5794               Mattingly v. R.J. Corman R.R. Grp., LLC                       Page 19


       Mattingly did not file a formal Rule 56(d) affidavit regarding the audit materials. Nor did
he file any language with the district court setting forth “specified reasons, [that he could not]
present facts essential to justify [his] opposition” pursuant to Rule 56(d). Thus, Mattingly did not
preserve the issue of whether the district court abused its discretion in not ruling on his pending
objections regarding discovery. See Plott, 71 F.3d at 1196–97 (holding that failing to provide a
contemporary affidavit seeking additional discovery to oppose summary judgment precludes a
finding of an abuse of discretion).

                                                IV.

       For these reasons, we AFFIRM the judgment of the district court.