Metrom Rail, LLC v. Ground Transportation Systems USA, Inc. et al.

I'll research this case thoroughly before drafting the overview.

Good initial results. Let me dig deeper into the IPRs, the parties, and the current posture.

Case Overview and Background

Parties. Plaintiff Metrom Rail, LLC is a small, privately held operating company based in Crystal Lake, Illinois, founded in 2010 by Jim Marchi (CEO) and Rick Carlson Sr. (COO). It is a genuine practicing entity, not a classic NPE/PAE: it designs and sells ultra-wideband ("UWB")-based rail safety hardware — the AURA product line (Collision Avoidance System, Positive Train Control System, Worker Protection System) — and was an MTA "Genius Transit Challenge" finalist (Dec. 2017) and winner (Mar. 2018). Contemporary coverage describes it as a roughly 40-person shop whose UWB technology was regarded as a first in the rail industry (Daily Herald, 1/22/2018; Metrom AURA datasheets). Litigation-tracker databases consulted did not flag Metrom as an NPE/PAE (see PatentPia litigation record for 1:23-cv-02920). The defendants are two much larger rail suppliers: Ground Transportation Systems USA, Inc. (GTS USA) — the former Thales ground-transportation/signaling business in the U.S., which appears in later filings as Hitachi Rail GTS USA Inc. after Hitachi Rail closed its €1.66 billion acquisition of Thales' GTS business on May 31, 2024 (Railway Age; Hitachi Rail press release) — and Piper Networks, Inc., a Delaware corporation headquartered in San Diego that "holds itself out as a rail engineering solutions provider and systems integrator" (S.D.N.Y. opinion, Metrom Rail v. MBTA, 1:25-cv-10417-DLC, Dkt. 113). These two were severed out of a broader 2022 Delaware suit that also named Siemens Mobility, Thales Transport & Security, Thales USA, and Humatics Corp. (D. Del. C.A. No. 22-49-RGA).

Accused technology and asserted patents. Metrom accuses the defendants' UWB-based train-positioning and protection "overlay" systems — not legacy CBTC — of infringement. As reflected in the amended complaint, the accused MTA/NYCT system uses wayside beacons/"anchors" and carborne UWB "nodes" to resolve train position continuously and feed it into train control (complaint analysis, Metrom v. GTS USA, 1:23-cv-02920). In the related MBTA matter, the accused products are Piper's Rail Positioning System (RPS) and Automatic Train Protection-Overlay (ATP-O), including the Green Line Train Protection System (GLTPS) awarded under a $113 million MBTA contract approved Feb. 26, 2025 (S.D.N.Y. 1:25-cv-10417, Dkt. 113). The four patents the case metadata lists as asserted here — U.S. 8,812,227, 10,179,595, 10,737,709, and 10,778,363 — span two Metrom families: the '227 patent ("collision avoidance system for rail line vehicles," claiming vehicle-mounted modules that use UWB time-of-flight ranging, plus GPS, to determine separation distance between rail vehicles; filed from a May 19, 2011 priority chain); the '595 and '709 patents ("worker protection system," covering UWB work-zone systems that alert on-track workers and train crews and can brake a train before it violates a protected work zone); and the '363 patent, a further member of Metrom's rail safety/positioning portfolio that also appears on the docket's Patent/Trademark report (Dkt. 3). I could not independently verify the '363 patent's exact title and claim scope from the sources reviewed, so I flag that sketch as unconfirmed; the docketed amended complaint also referenced the related U.S. 9,043,131 patent, which has since been invalidated (see below).

Posture, venue, and why it matters. Metrom filed the original action on Jan. 13, 2022 in the District of Delaware (C.A. 22-49-RGA, Judge Richard G. Andrews). On March 22, 2023, Judge Andrews granted in part and denied in part the defendants' motions to dismiss, dismissing direct-infringement claims against Humatics and Piper (among other counts), and granted severance into one case against Siemens/Humatics and another against Thales (now GTS USA/Hitachi) and Piper (D. Del. Dkt. 23; S.D.N.Y. Dkt. 23). The Thales/Piper case was opened as C.A. 1:23-cv-00314-RGA and, by joint stipulation, transferred to the S.D.N.Y. on April 6, 2023, becoming 1:23-cv-02920 (D. Del. Dkt. 25; S.D.N.Y. Dkt. 26). It was initially assigned to Judge Analisa Torres, then reassigned to Judge Denise L. Cote on April 12, 2023, with Magistrate Judge Jennifer Willis designated (S.D.N.Y. docket). Venue matters here because the accused deployments are New York-area transit systems (NYCT/MTA), and S.D.N.Y. is where the defendants' allegedly infringing offers/sales and installations occurred — S.D.N.Y. also became the consolidation point for Metrom's parallel campaigns (companion case 1:23-cv-03057-MKV against Siemens/Humatics, and the later MBTA case 1:25-cv-10417-DLC). Per a September 2023 PTAB filing, this case is currently stayed pending IPR (PTAB petition, 9/26/2023; see also the case's "pending/stayed" status). The case is notable for three reasons. First, it is an unusual "small innovator vs. global incumbents" assertion in which Metrom's own commercialized AURA CAS product was central to the secondary-considerations fight — and the courts rejected Metrom's nexus/coextensiveness showing. Second, its IPR linkage is dispositive: Siemens Mobility and co-defendants filed IPR2023-00468 and IPR2023-00470 on Jan. 13, 2023 (instituted June 23, 2023); the June 18, 2024 final written decisions held all claims of the '227 patent unpatentable and claims 1–16 of the '131 patent unpatentable, while upholding '131 claims 17–20 (see IPR2023-00468 summary). On appeal, the Federal Circuit issued a nonprecedential decision on May 11, 2026 (Nos. 24-2223/24-2236) rejecting Metrom's commercial-success and nexus arguments regarding AURA (CAFC opinion; CourtListener); the S.D.N.Y. subsequently treated the '227 claim as moot and the '131 patent as "no longer assertable" (Metrom v. MBTA, Dkt. 113). Third, the underlying market context is significant: Metrom's UWB overlay was positioned as a lower-cost alternative to multi-billion-dollar CBTC retrofits (the complaint cites MTA's Flushing-line CBTC conversion at $588 million and nine years), and Metrom alleges the defendants copied its technology — including Piper's hiring of former Parsons engineers who worked on Metrom's MBTA bids, and Siemens' UWB patent filings rejected over Metrom's patents. A further IPR, IPR2024-00947 (filed May 22, 2024 by Siemens Mobility, GTS USA, Piper, and Humatics), targets an additional Metrom patent, underscoring that the stays in these cases are driven by a coordinated, multi-patent IPR defense rather than by the merits of the district court pleadings.

Caveats: party names, case number, court, and asserted patents are taken as given; the '363 patent's technical scope and the exact current status of each asserted claim in 1:23-cv-02920 after the May 2026 Federal Circuit ruling are not fully verifiable from the public sources reviewed and should be confirmed against the live docket.

I'll research this case thoroughly, starting with the original Delaware action and the SDNY transferred case.

Let me research the PTAB proceedings and the June 18, 2024 PTAB decision.

Metrom Rail, LLC v. Ground Transportation Systems USA, Inc. et al., No. 1:23-cv-02920 (S.D.N.Y.)

Scope note: The case summary supplied above already covers the transfer/severance from the Delaware action and the general "IPR-driven stay" posture. The chronology below adds the docket-level events, the PTAB record, and the appellate outcome that post-date that summary. Facts I could not verify against a primary source are flagged.

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1. Filing & initial pleadings

Counterclaims: I found no well-sourced record of affirmative counterclaims (e.g., declaratory judgment of invalidity/non-infringement) by GTS USA or Piper in 23-cv-02920. Defendants' posture in Delaware was defensive (motions to dismiss/sever), and the case was stayed before any answer-cycle litigation matured. Treat "no counterclaims" as an inference from the docket, not a documented fact.

2. Transfer to S.D.N.Y. and reassignment

• 2023-04-06 — Case transferred in from D. Del. (D. Del. No. 1:23-cv-00314), docketed in S.D.N.Y. as 1:23-cv-02920; initially assigned to Judge Analisa Torres.
• 2023-04-12 — Reassigned to Judge Denise L. Cote; initial pretrial conference set for 2023-04-28; Magistrate Judge Jennifer Willis designated. (Docket at Justia Dockets.)
• 2023-04-18/27 — Pro hac vice admissions for Metrom's team (Howard N. Wisnia; Lora A. Brzezynski; Alejandro Menchaca; Gregory C. Schodde) — McAndrews, Held & Malloy and Farnan LLP on the plaintiff side; Faegre Drinker (Brzezynski/Rahmeier) on the GTS side.

3. The parallel PTAB proceedings and the stay

Petitions filed 2023-01-13 (same day, jointly by Siemens Mobility, GTS USA, Humatics and Piper; Thales USA identified as an RPI): IPR2023-00439, -00452, -00460, -00468 and -00470. The litigation docket reflects service of a Notice of Filing of Inter Partes Review Petitions on 2023-03-22.

• IPR2023-00470 (U.S. 8,812,227) — instituted 2023-06-23; FWD 2024-06-18: all challenged claims 1–28 unpatentable as obvious over Grisham (U.S. 6,759,948) in view of Nixon (WO 03/009254) and Douglas (U.S. 8,874,359). (FWD PDF)
• IPR2023-00468 (U.S. 9,043,131) — instituted; FWD same day, holding claims 1–16 unpatentable but claims 17–20 not shown unpatentable (limitation 17C, "a first wireless communications antenna operable to send and receive data representing the separation distance over the air," not disclosed by Grisham). The two FWDs were appealed together.
• IPR2024-00947 (U.S. 9,731,738 — a related Metrom patent, not one of the four listed in the case metadata**)** — filed 2024-05-22; POPR 2024-08-28; institution DENIED 2024-11-19/20 by APJs Powell, White and Dougal, with § 325(d) central to the denial (art substantially the same as what the examiner considered). Petitioners sought Director Review on 2024-12-19; a delegated Director Review decision followed in spring 2025. (GreyB/IPVerse docket; McAndrews press release, 2024-11-21)

Caveat: I was unable to confirm from a primary source the patents and outcomes of IPR2023-00439, -00452 and -00460. The pattern of five same-day petitions against five asserted patents makes it likely they correspond to the '363, '709 and '595 patents and/or the '131, but the mapping of each number to each patent and any institution/denial outcomes are unverified.

Effect on the litigation — the stay. The S.D.N.Y. action was stayed pending the IPRs. The earliest direct confirmation I located is a 2023-09-26 paper in IPR2023-00470 stating that "Metrom Rail, LLC v. Ground Transportation Systems USA, Inc. & Piper Networks, Inc. … 23-cv-02920-DLC, [is] currently stayed," while the severed Siemens/Humatics case proceeded as Metrom Rail, LLC v. Siemens Mobility, Inc. and Humatics Corp., No. 23-cv-03057-MKV (Judge Mary Kay Vyskocil). The exact stay order date and its terms (e.g., whether it was a full stay, and any IPR-termination trigger) are not verified; the metadata in this task lists the case as "pending/stayed," consistent with that record.

4. Claim construction (Markman)

• No district-court Markman proceeding was reached in 23-cv-02920 — the case was stayed before claim-construction briefing, so there is no S.D.N.Y. Markman order or opinion to report.
• The only substantive claim construction in the dispute occurred at the PTAB and on appeal. The pivotal term was "data representing the separation distance" in claim 17 of the '131 patent, which became the dispositive issue on cross-appeal (see §6).
• The district-court pleading analysis flagged the likely construction battlegrounds had the case reached Markman: "decentralized control operations" ('363 claim 1) and "collision avoidance system" ('227), given that the accused MTA systems interface with legacy centralized zone controllers.

5. Discovery milestones with strategic significance

District-court discovery was largely dormant due to the stay. The strategically significant discovery occurred in the IPRs:

• 2023-07-11/08-02 — Board denies Patent Owner's motion for additional discovery — a meaningful early loss for Metrom, which had sought discovery going to the petitioners' alleged copying/derivation narrative (Piper sales collateral, Garcia/D. Garcia–Metrom emails and conference materials, MTA Genius Award photo, archived Piper webpages, AURA/HELIX product specs).
• 2023-08-28 — Deposition of petitioners' expert Scott Andrews.
• 2023-11-15 — Deposition of Metrom's Kurt Gunther (named '227/'131 inventor; his testimony on industry skepticism of UWB became the backbone of Metrom's secondary-considerations case).
• 2024-03-28 — Oral hearing in IPR2023-00470 (Tr., Paper 70). The Board's FWD credits Metrom's evidence of skepticism and commercial success but finds no nexus to the claims because the AURA CAS product had significant unclaimed features (machine-function monitoring, remote data reporting). This nexus failure is what Metrom attacked on appeal and what the Federal Circuit affirmed.

6. Trial, verdict, post-trial motions

There has been no trial, verdict, JMOL, new-trial or fee motion in 23-cv-02920. The operative "trial-type" adjudication in this dispute has been the PTAB final written decisions and the resulting Federal Circuit appeal.

*Federal Circuit — Metrom Rail, LLC v. Siemens Mobility, Inc., Nos. 24-2223, -2236, -2264 (consolidated), nonprecedential opinion issued 2026-05-11:*

• Metrom appealed the adverse '227 and '131 rulings; petitioners cross-appealed the survival of '131 claims 17–20.
• Affirmed-in-part / reversed-in-part: (i) all '227 claims and '131 claims 1–16 held unpatentable — affirmed, with the Court rejecting Metrom's Fox Factory nexus arguments and single-reference/claim-1 arguments (the latter forfeited as untimely sur-reply arguments); (ii) '131 claims 17–20 — reversed, now unpatentable, because the Board's construction of "data representing the separation distance" (requiring the computed distance) was legally wrong; the correct reading covers data used in the time-of-flight calculation, which Metrom conceded Grisham transmits over the air. Notably, the Court relied on Metrom's own district-court complaint construction ("data used to determine the time of flight") as a check on the Board's reading.
• Judge Taranto concurred-in-part and dissented-in-part, objecting that the majority resolved the cross-appeal on a claim-construction theory Siemens never presented to the Board or the Court, implicating party-presentation and forfeiture principles (Clark v. Sweeney; In re Google Tech. Holdings). (Opinion PDF; Fed. Cir. Blog, 2026-05-12; IP Law Daily summary)
• Post-judgment appellate motion: Metrom filed a Combined Petition for Panel Rehearing and Rehearing En Banc (document[ed] June 2026), squarely aimed at the Taranto dissent's party-presentation point. Whether rehearing was granted is not confirmed as of 2026-09-16.

Caption/party changes: On 2024-09-05 Ground Transportation Systems USA Inc. moved to modify the official Federal Circuit caption; by 2024-10-02 GTS USA was succeeded in the caption by Hitachi Rail GTS USA Inc., fka Ground Transportation Systems USA Inc. (reflecting Hitachi's acquisition of the former Thales ground-transportation business).

7. Ultimate disposition / present posture

• No settlement, consent judgment, or dismissal has been reported in 23-cv-02920. The case remains pending and stayed in S.D.N.Y. per the authoritative metadata.
• Practical effect on the asserted patents: Two of the five originally asserted patents have been fully invalidated as to all claims by final, appealable PTAB/CAFC determinations — the '227 (all claims) and the '131 (claims 1–16 affirmed unpatentable; 17–20 reversed into unpatentability). With the '227 gone, the S.D.N.Y. action's live theory now runs on the '363, '709 and '595 patents (the four patents listed in the case metadata incl. the '131). The last reported substantive district-court activity is a ruling denying Piper's motion to dismiss for failure to state a claim — Law360, dated on or about 2026-05-21 — in which the court "found the suit gave Piper proper notice of the infringement claims." That report does not specify the docket number; it most plausibly reflects the renewed motion after transfer by the D. Mass. court (see §8), or a renewed motion in 23-cv-02920 once the stay was lifted. The exact docket entry and the date the stay was lifted are unverified.
• Status of the asserted patents: U.S. 8,812,227 — all claims cancelled (subject only to any rehearing/en banc relief). U.S. 9,043,131 — all claims held unpatentable on appeal. This is a materially adverse record for Metrom and reduces the leverage value of the S.D.N.Y. case.

8. Related/parallel litigation worth tracking

• Metrom Rail, LLC v. Siemens Mobility, Inc. & Humatics Corp., No. 1:23-cv-03057-MKV (S.D.N.Y.) — the severed Siemens/Humatics case; second amended complaint filed there; also stayed/aligned with the IPRs.
• Metrom Rail, LLC v. Massachusetts Bay Transportation Authority (D. Mass. No. 25-cv-11446-ADB; S.D.N.Y. No. 1:25-cv-10417) — MBTA Green Line/Piper dispute on the same patent family. Judge Burroughs' 2025-12-08 order (i) granted Piper's motion to dismiss/transfer, holding Metrom failed to make a prima facie showing of venue under TC Heartland and transferring the Piper claims to S.D.N.Y.; (ii) severed and stayed the MBTA claims under the traditional stay factors (not reaching the customer-suit exception); and (iii) denied without prejudice Metrom's preliminary-injunction/expedited-discovery motions and the MBTA's motion to dismiss. (Finnegan D. Mass. update; Mass. Lawyers Weekly summary)

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Key takeaways for case assessment

1. The IPRs, not the district court, have decided this dispute's patent merits. The '227 and '131 are effectively out of the case after the Federal Circuit's 2026-05-11 decision; the stay of 23-cv-02920 was the mechanism that gave the PTAB that priority.
2. The single most important recent development is the nonprecedential Metrom opinion's sua sponte construction on cross-appeal, and Judge Taranto's dissent — the vehicle for Metrom's June 2026 rehearing petition. If rehearing en banc is granted, '131 claims 17–20 could theoretically be revived, but that is a low-probability path.
3. Metrom's secondary-considerations case failed for lack of nexus (non-coextensive AURA CAS product), which is worth noting for any other Metrom assertions in the '363/'709/'595 families, since the same attack — unclaimed features defeating the nexus presumption — is now road-tested.
4. Unverified items I would confirm against PACER/PTAB: the exact stay order and lift date in 23-cv-02920; the mapping and dispositions of IPR2023-00439/-452/-460; whether the May 2026 Piper dismissal ruling issued in 23-cv-02920 or in the transferred MBTA/Piper action; and the disposition of Metrom's rehearing petition.

I'll research the counsel of record for Metrom Rail in this SDNY action.

Let me pull the specific docket and party counsel listings for this case number.

Let me get the party/counsel listing from the docket and confirm local counsel arrangements.

Counsel of Record — Plaintiff Metrom Rail, LLC

Metrom Rail, LLC v. Ground Transportation Systems USA, Inc. et al., No. 1:23-cv-02920 (S.D.N.Y.) (Judge Denise L. Cote)

A caveat up front: SDNY docket entries for this case are public (no sealing of appearance info that I could find), but the docket in this action is thin — after the case was transferred in from Delaware on April 6, 2023 and stayed on April 21, 2023, the only plaintiff-side activity was three pro hac vice admissions. Because the case is stayed, no trial team has been formally "rolled out," so the roster below is drawn from the docket, the transferred Delaware docket, and parallel PTAB/Federal Circuit filings by the same firm. I flag where a person is confirmed on the SDNY docket versus only on the related PTAB/CAFC record.

Confirmed on the 1:23-cv-02920 docket (plaintiff side)

Local counsel: I found no SDNY-admitted local counsel of record for Metrom. The S.D.N.Y. has no local-counsel requirement, and Metrom's team is Chicago-based (McAndrews) plus Delaware counsel, so the PHV route (Schodde, Menchaca, Ruben) is how the team appears. If a New York firm has been retained, it has not appeared on this docket.

Delaware counsel of record (original action / transferor court)

• Farnan LLP (Wilmington, Delaware) — identified as plaintiff's Delaware counsel on the original complaint in the predecessor action, Metrom Rail, LLC v. Ground Transportation Systems USA, Inc., No. 1:23-cv-00314 (D. Del.) (the analysis of D.I. 9 lists "Plaintiff's Counsel: Farnan LLP; McANDREWS, HELD & MALLOY, LTD."), and the case documents were carried into S.D.N.Y. as D.I. 26. I could not verify from the sources I reviewed which individual Farnan attorney signed the pleadings, so I am not naming one. This is the one place where the record is incomplete for my purposes.

Same firm, related matters (not confirmed as SDNY counsel of record)

These McAndrews attorneys appear for Metrom in the IPR2023-00468/-00470, IPR2024-00947 and the Fed. Cir. No. 24-2223 appeal, but I found no SDNY appearance for them in 1:23-cv-02920:

• Rajendra A. Chiplunkar — McAndrews, Chicago; Reg. No. 34,389-era backup counsel; was admitted PHV in the Delaware action and entered his appearance on the Federal Circuit appeal (with Schodde and Ruben).
• Ronald "Hank" Spuhler — McAndrews, Chicago; Reg. No. 52,245; backup counsel in the IPRs.
• Christian Havel Hallerud — McAndrews, Chicago; listed on the Federal Circuit docket for Metrom.
• Ashley M. Ratycz — McAndrews; listed as backup counsel in Patent Owner's mandatory notices.

Relevant experience / notables (one line each)

• Gregory C. Schodde (McAndrews) — Patent-owner lead counsel for Metrom across the IPR2023-00468/-00470 and IPR2024-00947 challenges by Siemens/GTS USA/Humatics/Piper, and appellant's counsel on the consolidated Fed. Cir. appeal (No. 24-2223, Metrom Rail v. Siemens Mobility) and its combined petition for panel rehearing/rehearing en banc; McAndrews is a Chicago IP-only firm recognized in World IP Review rankings, and its client list includes Metrom Rail, Accord Healthcare, and Columbia Sportswear.
• Alejandro Menchaca (McAndrews) — Long-tenured McAndrews patent litigator; part of the Metrom IPR team that defeated institution in November 2024 (the USPTO declined review after McAndrews showed the petition's grounds were substantially the same as art already considered during prosecution).
• Philipp Ruben (McAndrews) — Registered patent attorney (Reg. No. 78,361), junior member of the Metrom IPR/appellate team.
• Farnan LLP — Wilmington boutique known for Delaware patent/Chancery litigation; served as Metrom's Delaware forum counsel for the original 2022–23 complaint before transfer/severance split the case into this action and No. 1:23-cv-03057 (Siemens/Humatics).

Two record notes worth carrying forward

1. Party-name drift: the S.D.N.Y. docket now often reads Metrom Rail, LLC v. Hitachi Rail GTS USA Inc. because Ground Transportation Systems USA was renamed Hitachi Rail GTS USA Inc. after Hitachi's acquisition of Thales' GTS business — the defense side is represented by Faegre Drinker (Lora A. Brzezynski, PHV granted at D.I. 38; Thatcher A. Rahmeier, Wilmington) for GTS/Hitachi, and by Wisnia PC / Dority & Manning for Piper. Don't mistake D.I. 35/38 (Brzezynski) for plaintiff's counsel — those are defense filings.
2. Stay posture: D.I. 34 (Apr. 21, 2023) stayed the case in its entirety pending PTAB final written decisions on all patents-in-suit, requiring a joint status report within 14 days of those decisions. As of the Sept. 26, 2023 PTAB mandatory notice, the case was still described as "currently stayed." That stay is why the plaintiff's SDNY appearance roster stops at the April 2023 PHV orders.

If you need the Farnan signatory named precisely, the fastest confirmations are the signature block of the original D. Del. complaint (D. Del. C.A. No. 22-49-RGA, from which this case was severed) and the D.I. 9 First Amended Complaint; both should be pullable from PACER.

I'll research the docket and counsel appearances for this case.

I have partial information. Let me dig deeper into the SDNY docket entries and confirm which counsel represent which defendant.

Let me pull the full docket entry list and check for any additional appearances (including local counsel) and the case's current status.

Bottom line: Because this action was transferred from Delaware (D. Del. 22-49-RGA) and then stayed in its entirety on April 21, 2023 — before either defendant answered — the SDNY docket contains only a thin set of defense appearances. Two firms have formally appeared: Faegre Drinker Biddle & Reath LLP for Ground Transportation Systems USA Inc. (now Hitachi Rail GTS USA Inc.) and Wisnia P.C. for Piper Networks, Inc. No in-house counsel and no New York local counsel are identified in any filing I could locate; a caveat on completeness follows.

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1. Ground Transportation Systems USA Inc. (renamed Hitachi Rail GTS USA Inc.)

2. Piper Networks, Inc.

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What I could not verify (stated explicitly, not invented)

• No SDNY local counsel of record for either defendant. SDNY pro hac vice practice normally requires a sponsoring local attorney; the docket entries I could retrieve do not name one for Piper or GTS. It is possible a local attorney is listed in the ECF "attorney to be noticed" field or on a notice of appearance I could not retrieve — treat this item as unconfirmed.
• No in-house counsel appearance for either Hitachi Rail GTS or Piper.
• No sealed filings affecting counsel. The stay (D.I. 34) froze the case before any Rule 12 motion or answer, so there is little more than appearances and pro hac vice papers on the defense side.
• Attorney listings beyond D.I. 38 (i.e., any post-2023 substitutions, withdrawals, or revised appearances after the June 18, 2024 PTAB final written decisions and the May 11, 2026 Federal Circuit decision) were not retrievable within my search budget. If the stay has been lifted and the case reactivated, the appearance list may have changed.

Why the defense roster looks thin (context)

The underlying Delaware action, Metrom Rail, LLC v. Siemens Mobility, Inc., No. 22-49-RGA, was severed by Judge Andrews' March 22, 2023 memorandum order: Siemens/Humatics went to one case (S.D.N.Y. 1:23-cv-03057) and Thales (now GTS)/Piper to this case. The two defendants were represented by separate litigation teams — Faegre Drinker for GTS and Wisnia P.C. for Piper — but coordinated in the PTAB, where they filed as a single petitioner group (Siemens, GTS, Humatics, Piper). That unified PTAB posture explains why the same names recur across the district and IPR dockets: Rahmeier as the group's designated IPR lead counsel (GTS/Faegre Drinker), Wisnia as Piper's IPR lead counsel, Crowell & Moring (Supko, James, Schmitz, Galluzzo) for Siemens, Wolf Greenfield (Nieberg, Speed) for Humatics, and Dority & Manning as Piper's IPR backup. On appeal, GTS–Hitachi was represented by Brzezynski (Faegre Drinker, DC) and Rahmeier (Faegre Drinker, Wilmington) per the Federal Circuit docket in No. 24-2223.

Key sources

• D. Del. 1:22-cv-00049-RGA, D.I. 51 / S.D.N.Y. 1:23-cv-02920, D.I. 23 — Memorandum Order (severance, Mar. 22, 2023).
• 1:23-cv-02920, D.I. 24 (joint stipulation, signed Rahmeier for GTS); D.I. 28 (Wisnia PHV, filed by Piper); D.I. 33 (joint letter motion to stay, "filed by Piper Networks, Inc."); D.I. 34 (stay order, Apr. 21, 2023); D.I. 35 & 38 (Brzezynski PHV motion and grant).
• USPTO PTAB mandatory notices, IPR2023-00470 and IPR2024-00947 (Petitioner Updated Mandatory Notice Information, Oct. 2, 2024) — firm/role/address data for Rahmeier, Kachmer, Wisnia, Moore, Cunningham, et al.
• CourtListener, Fed. Cir. No. 24-2223, parties/attorneys page (Brzezynski and Rahmeier for Hitachi Rail GTS USA Inc.).
• Federal Circuit opinion, Metrom Rail, LLC v. Siemens Mobility, Inc., No. 24-2223 (May 11, 2026) (nonprecedential).

If you want, I can attempt a PACER-level pull of the current ECF attorney list for 1:23-cv-02920 (and the related 1:23-cv-03057 and any 2025–26 Piper/MBTA action in SDNY) to catch any post-2023 substitutions.