US 10336353

I'll search for authoritative information on this patent number, including any 2026 CAFC activity.

Let me confirm the actual claim set of US 10,336,353 specifically (not its siblings), and check for any 2026 litigation/PTAB activity naming that exact number.

Let me verify the remaining independent claim(s) of the '353 patent specifically.

US Patent 10,336,353 B2 — "Worker Protection System"

Grounding sources: Google Patents (patents.google.com/patent/US10336353B2/en, fetched 2026‑09‑24; the authoritative full text supplied in the prompt), RPX Insight patent record, uspto.report family record for the related continuation 10,926,783, and CAFC 2026 opinion materials.

Bibliographic data

Abstract (verbatim)

"Systems and methods are provided for worker protection. The worker protection systems comprise a plurality of alert devices, comprising one or more wearable personal alert devices, each worn by a person (e.g., worker), and one or more companion alert devices that broadcast alerts or signals triggering alerts. The companion alert devices comprise vehicle-mounted alert devices, configured for operation on vehicles (e.g., trains), and wayside detection units, configured for placement on or near paths of the vehicles. The wayside detection units may be operable to autonomously detect and track the vehicles."

Plain‑language overview of the disclosure

The patent describes a railway proximity‑warning ("worker protection") architecture built from up to three device classes: (1) portable alert devices (PADs) worn by track workers; (2) vehicle alert devices (VADs) mounted on trains; and (3) wayside detection units (WDUs) placed on/near the track. Alerts can be triggered by speed as well as distance (e.g., TTA, distance‑from‑train, and low‑speed close‑proximity thresholds), only when the range is decreasing, and can be location‑customized (e.g., via NFC re‑configuration stations) and logged. Devices may act as repeaters and form collaborative/cascading alert chains.

Independent claims — plain language

Claim 1 (system for worker protection — wayside detection unit). A worker‑protection system built around a wayside detection unit placed on or near a vehicle's path. The unit must include, in combination:

• a housing enclosing its components;
• a support structure (e.g., tripod) holding/supporting it in place;
• a power supply;
• one or more sensory components for detecting, monitoring and/or tracking vehicles;
• a communication component with one or more antennas for transmitting/receiving wireless signals; and
• one or more circuits that process signals/data and perform applications or functions of the unit,

where the unit is configured to communicate signals/messages to one or more companion alert devices while providing monitoring and tracking services in a work site.
(Verbatim text per RPX Insight: https://insight.rpxcorp.com/patent/US10336353B2 — "1. A system for worker protection, the system comprises: a wayside detection unit, configured for placement on or near path of a vehicle…wherein the wayside detection unit is configured to communicate signals and/or messages to one or more companion alert devices while providing monitoring and tracking services in a work site.")

Second independent claim — uncertainty (flagged). I could not obtain an authoritative verbatim copy of the remaining independent claim(s) of the '353 patent from the sources retrieved. What is reliably known:

• The '353 patent carries 20 claims (consistent with its direct continuation, US 10,926,783, which also carries 20 claims and whose claim 14 is an independent claim to "a compact wearable personal alert device").
• USPTO unity‑of‑invention materials for the Metrom Rail family describe a claim group "drawn to a system for worker protection… a compact wearable personal alert device, configured for use by a worker, the personal alert device comprising an attachment structure for attaching it to the worker or an item used by the worker; [to] generate, in response to signals received from a companion alert device, a safety alert; and output, via one or more indicator components, one or more alert indications to the worker."

Accordingly, the likely second independent claim is directed to the wearable personal alert device (attachment structure + receive companion signal + generate safety alert + output visual/audio/tactile indication). I state this as an inference, not confirmed claim text; the exact claim number and wording should be verified against the granted patent's claim sheet (USPTO PatentCenter / the patent PDF).

CAFC 2026 docket check — no hit for this number

Searches of the Federal Circuit's 2026 activity produced no 2026 CAFC docket naming US 10,336,353. The only 2026 Federal Circuit matter involving this assignee is:

• Metrom Rail, LLC v. Siemens Mobility, Inc., Nos. 2024‑2223, 2024‑2236, 2024‑2264 (Fed. Cir., nonprecedential opinion May 11, 2026), on appeal from PTAB IPRs IPR2023‑00468 and IPR2023‑00470. This case concerns U.S. Patent Nos. 9,043,131 and 8,812,227 (collision‑avoidance systems claiming a May 19, 2011 priority date) — not 10,336,353. The court affirmed unpatentability of all claims of the '227 patent and claims 1–16 of the '131 patent, and reversed the Board as to claims 17–20 of the '131 patent. A combined petition for panel rehearing and rehearing en banc was filed by Metrom (June 2026).
  • Sources: https://cafc.uscourts.gov/2026/05/11/page/2/ ; https://law.justia.com/cases/federal/appellate-courts/cafc/24-2223/24-2223-2026-05-11.html

Likewise, I found no IPR petition or PTAB proceeding captioned against 10,336,353 specifically. The 2023 Metrom IPR cluster I saw (‑00439, ‑00452, ‑00460, ‑00468, ‑00470) targets other Metrom patent numbers.

Caveats and uncertainties

• Priority nuance: Google Patents labels the 2016‑03‑23 date a priority "assumption"; the '353 specification itself states it is a CIP of 15/078,427 (filed Mar. 23, 2016) and claims benefit of provisional 62/350,520 (filed June 15, 2016). Sibling patents in the family also trace back to provisional 62/177,683 (Mar. 23, 2015) via 15/078,427. Effective priority for any given claim therefore depends on which disclosure the claim relies on.
• Claim set: Only claim 1 of the '353 patent was obtained verbatim; the full 20‑claim set and the exact independent‑claim boundaries were not authoritatively confirmed from the sources retrieved. Treat the "second independent claim" description above as an inference from family/unity documents.
• No live USPTO/PTAB status snapshot: I did not retrieve a current PatentCenter transaction history for 15/623,996, so maintenance‑fee/expiry details rest on Google Patents' stated "adjusted expiration 2036‑05‑19."

If you want, I can attempt to pull the full claim sheet for the '353 patent from a specific source (e.g., the granted‑patent PDF) to lock down the independent‑claim text and count.

I'll search for litigation involving US patent 10336353.

Let me refine my search, since this patent is assigned to Metrom Rail LLC.

The results so far reference Metrom Rail's other patents ('131, '227, '738), not specifically the '353 patent. Let me search more precisely.

Answer: No litigation specifically asserting US Patent 10,336,353 was found

I searched for litigation involving US 10,336,353 (Worker protection system, Metrom Rail, LLC). Based on the sources I could reach (CourtListener/RECAP dockets, Justia, PACER Monitor, CAFC opinions, PTAB filings, and secondary litigation-reporting sources), I could not identify any lawsuit, IPR, or other proceeding in which US 10,336,353 ("the '353 patent") is specifically named as an asserted or challenged patent. I want to be explicit about that rather than infer it: the absence of a hit is not proof the patent has never been asserted, and I was not able to directly query the Unified Patents litigation portal or run an exhaustive PACER docket-text search for the patent number.

To be clear about the distinction the instructions emphasize: many results referenced Metrom Rail and its rail-safety patents — but those references are to sibling/family patents (e.g., U.S. 9,043,131, U.S. 8,812,227, U.S. 9,731,738), not to 10,336,353. I am not substituting those cases for the '353 patent.

Why the '353 patent is a plausible candidate for litigation (context, not a finding)

US 10,336,353 is assigned to Metrom Rail, LLC (Lakemoor, Illinois), the same plaintiff that has waged a multi-front campaign over its train-collision-avoidance / worker-protection patent family, of which the '353 patent is a continuation-in-part (priority via App. 15/078,427, which issued as U.S. 10,179,595). The '353 patent shares inventors with that family (Carlson, Gunther, Woitel, Cygnus, Strezev, Plutt) and the same "worker protection system" subject matter. So the family is heavily litigated — but the asserted patents I found in those suits are the other members.

Closely related Metrom Rail litigation (for context — these do NOT involve the '353 patent)

These are the cases surfaced in my search; I flag them because they are the same patent family/owner, but none is a '353 action:

Related PTAB proceedings (again, not on the '353 patent): IPR2023-00468 and companion IPRs challenging U.S. 9,043,131 and U.S. 8,812,227, brought by Siemens Mobility, Ground Transportation Systems USA, Humatics, and Piper Networks against Metrom Rail.

Bottom line

• Known litigation involving US 10,336,353: none identified. No plaintiff, defendant, jurisdiction, case number, or filing date can be attributed to the '353 patent on the evidence available to me.
• The '353 patent is owned by Metrom Rail, LLC, whose other rail-safety patents ('131, '227, '738) are the subject of active and appealed litigation and IPRs. If you need certainty, the definitive step would be a full-text PACER docket search for "10,336,353" and a direct check of the Unified Patents litigation database and the USPTO/PTAB assignment and proceeding records — I could not complete those exhaustive checks here, and I am not asserting a negative result beyond the sources actually searched.

If you'd like, I can next attempt a targeted docket-text search for the patent number in specific district courts (e.g., D. Del., S.D.N.Y., D. Mass., N.D. Ill.) to try to close that gap.

I'll check the structured proceedings list against what's publicly searchable, then verify with targeted searches.

The structured block says no proceedings on the '353 patent. Let me verify against PTAB dockets and check whether any proceeding touched this specific patent number.

Let me confirm the full Metrom Rail IPR docket and check whether the '353 patent was ever named in a petition or the district court case.

PTAB / AIA Trial Proceedings — US 10,336,353 B2 ("Worker protection system," Metrom Rail LLC)

Bottom line up front: there are zero AIA trial proceedings on this patent. The structured PTAB-proceedings block (USPTO Open Data Portal) returns no IPR, PGR, or CBM for US 10,336,353. I ran targeted searches of PTAB dockets, the Federal Circuit docket, and Metrom Rail litigation coverage and found no petition, institution decision, or FWD naming this patent. I also checked whether any proceeding naming this number existed and surfaced none. This is a verified absence, not a gap in the data — with one caveat noted below.

Proceedings overview

Total AIA trial proceedings on US 10,336,353: 0 — no active proceedings, no claims invalidated, no claims sustained, no settlements, no institution denials, because no petition has ever been filed. Defensive posture: the patent is completely untested at the PTAB, which cuts both ways — there is no invalidating FWD to hand a defendant a free win, but there is also no IPR record hardening the claims, and Metrom Rail's sibling patents in adjacent families have taken heavy casualties (all claims of US 8,812,227 and, after appeal, all of US 9,043,131 held unpatentable).

⚠️ Caveat on the structured data. The "no PTAB activity" default is correct for this patent number, but note that this patent is not listed among the patents Metrom asserted in its January 2022 Delaware complaint (per Metrom's 2022-01-18 press release, that suit asserts US 10,778,363, 8,812,227, 9,043,131, 10,737,709, and 10,179,595 — not 10,336,353). So the absence of IPRs is consistent with the absence of high-stakes assertion activity against this specific number.

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Related proceedings — not on US 10,336,353 (context only)

I am including these because a defendant facing the '353 will inevitably confront them, but none of the proceedings below challenged US 10,336,353, and I have not conflated them with it. All are Metrom Rail patents from adjacent families.

Panel (IPR2023-00470 FWD): APJs Neil T. Powell, Stacey G. White, and Iftikhar Ahmed (opinion by Ahmed).
Panel (IPR2024-00947 institution denial): APJs Neil T. Powell, Stacey G. White, and Brent M. Dougal.
Petition grounds in the '227/'131 IPRs: § 103 obviousness, all claims. Primary reference US 6,759,948 (Grisham) on every ground, with WO 03/009254 (Nixon) for GPS functionality; secondary references included Richardson (2010 UWB tracking paper), US 8,874,359 (Douglas), Connell, Breed, McDaniel, Richards.
Federal Circuit: Metrom Rail, LLC v. Siemens Mobility, Inc., Nos. 2024-2223, 2024-2236, 2024-2264 (Fed. Cir. 2026-05-11), nonprecedential, affirmed-in-part and reversed-in-part (Judge Taranto concurring-in-part and dissenting-in-part on the claims 17–20 reversal). Opinion: https://cafc.uscourts.gov/opinions-orders/24-2223.OPINION.5-11-2026_2691571.pdf ; mirror: https://www.courtlistener.com/opinion/[10856969](/patent/10856969)/metrom-rail-llc-v-siemens-mobility-inc/ . Metrom subsequently filed a combined petition for panel rehearing and rehearing en banc; I could not confirm the disposition from retrieved sources — treat as flagged, unverified.

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Strategic summary

Claim status on US 10,336,353. No claim of this patent has been canceled, confirmed, or construed by the Board. Every claim is UNTESTED at the PTAB. The mixed outcomes you will find in the press are about different patents — critically, US 8,812,227 (all claims dead) and US 9,043,131 (all claims dead as of the 2026-05-11 CAFC reversal) are not this patent. If an assertion letter or complaint cites US 10,336,353, the "claims are already canceled" argument does not exist here. Equally, the patent owner cannot claim a PTAB win on this number.

Estoppel landscape. Because no IPR was ever filed against the '353, no § 315(e)(2) estoppel attaches to this patent at all. Siemens/Humatics/Piper/GTS — or any other defendant — retain full freedom to raise § 102/§ 103 art against the '353 in district court and to petition for IPR. Two practical points: (1) the § 315(b) one-year clock has not started for anyone unless they have been served with a complaint asserting the '353, and I found no public record of such service; (2) any new petition faces § 325(d) discretionary-denial risk if the art was already in the '353's prosecution history — that is exactly the theory that killed IPR2024-00947 against the '738 patent, so run a § 325(d) / Advanced Bionics screen before filing.

Pattern signals. The same petitioner group (Siemens Mobility + GTS USA + Humatics + Piper, with Thales USA as an RPI) filed a coordinated wave of six IPRs in early 2023 across the Metrom portfolio — a broad, deliberate portfolio attack, not a one-off. Metrom litigates aggressively: it won three institution denials on procedural grounds (§ 325(d)), lost the '227 and '131 outright, appealed, sought en banc rehearing, and before the Board it leaned hard on secondary considerations tied to its AURA CAS product (the Board and the CAFC both rejected nexus because AURA CAS has unclaimed "important features"). No defensive aggregator (e.g., Unified Patents) appears anywhere in the chain — this is competitor-driven, not troll-driven, and the art set is real rail/UWB collision-avoidance prior art (Grisham, Nixon, Richardson, Douglas).

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Recommended next steps

1. If you are a defendant now facing US 10,336,353: the PTAB gives you no gift. Do not rely on any FWD — there isn't one. Build your invalidity case from scratch, but start from the family IPR record: the '227/'131 FWDs (IPR2023-00468 and IPR2023-00470) and the CAFC opinion at https://cafc.uscourts.gov/opinions-orders/24-2223.OPINION.5-11-2026_2691571.pdf contain a Board- and court-vetted obviousness analysis of Grisham (US 6,759,948) that disposed of every claim of two Metrom patents. The 2026-05-11 CAFC disposition — "We conclude that there is no dispute that Grisham discloses sending and receiving data used to determine a separation distance using the time-of-flight technique over the air... we conclude that petitioners have shown that claims 17–20 of the '131 patent are unpatentable as obvious. We reverse" — is a strong proof point that this art set is lethal against Metrom's UWB claims, provided the claim-mapping is done properly.
2. Preserve your IPR window. No § 315(b) clock is running on the '353 until someone is served with a complaint asserting it. If you are served, note that the petition must be filed within one year of service; if you are sued alongside a co-defendant who was already served on the '353, confirm privity/RPI status.
3. If you are evaluating assertion risk generally: the absence of any PTAB challenge to the '353 — despite a well-resourced competitor group hammering the rest of the portfolio — is itself a signal. It is consistent with the '353 simply not being the asserted patent (it is not in the January 2022 Delaware complaint). Treat it as a secondary/backup patent in Metrom's portfolio rather than the tip of the spear.
4. Verify IPR2023-00439 before relying on any portfolio summary. It is identified only as a same-parties proceeding in the '363 mandatory notice; its patent number and disposition were not confirmed by my sources. Pull it from PTAB E2E (https://ptab.uspto.gov/) if it is relevant to your mapping.

Nothing above should be read as a statement that any claim of US 10,336,353 has been invalidated, sustained, or construed — none has.

I'll research the assignment record for US 10336353. Let me start with several targeted searches.

Let me dig deeper into the assignment record, litigation history, and corporate status.

Ownership & Assignment Analysis — US 10,336,353 B2 ("Worker protection system")

Patent under review: US 10,336,353 B2 · App. 15/623,996 · filed 2017-06-15 · granted 2019-07-02 · assignee of record Metrom Rail, LLC · status Active, Google Patents lists adjusted expiration 2036-05-19.
Verification link: https://assignmentcenter.uspto.gov/ (search patent number 10336353) and https://patents.google.com/patent/[US10336353B2](/patent/US10336353B2)/en

Data-integrity note up front: I could retrieve the existence, parties, and recording date of the assignment from Google Patents legal events, but the reel/frame number and the correspondent/attorney of record were not surfaced in any source I could reach. I will not invent them. Where the field is a gap, I say so.

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Inventors

• Residence data is drawn from the sibling patent US 10,737,709 B2 (Carlson et al.), same inventorship group: https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1550904](/patent/1550904) (Exhibit 1001 copy of the '709 patent).
• Employer at filing: Not stated on the face of US 10,336,353. However, all six are named on multiple Metrom Rail applications, the filing address cluster is Lake/McHenry County, Illinois (Crystal Lake / Lakemoor = Metrom Rail's HQ region), and the only recorded transfer is a pro-forma inventor→company assignment. The reasonable reading is that all six were Metrom Rail personnel or contractors at filing. I flag this as an inference, not a recorded fact.
• Unusual patterns: None detected. There is no evidence of inventors departing, no inventor-initiated assignments, and no inventor-to-third-party conveyances. The inventorship group is stable across the entire continuation family (US 10,896,589; 10,926,783; 11,492,027; 11,780,481; 12,122,436; 2025/0050921), which is the opposite of the "inventors bail out, portfolio fire-sales" pattern you asked me to watch for. Note that CEO James A. Marchi (co-founder) is NOT a named inventor on this patent — a normal arrangement, but worth recording because he is the declarant driving the litigation/invalidity defenses.

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Original assignee

Metrom Rail, LLC — Crystal Lake / Lakemoor, Illinois (HQ Lakemoor, IL per the company's own 2022 press release).

• Primary line of business: Railroad safety equipment — ultra-wideband (UWB)-based collision avoidance, train control, signaling, and roadway-worker protection. Founded 2010.
• Did they ship a product embodying the claims? Yes. Metrom's AURA® Maintenance-of-Way Collision Avoidance System (AURA CAS), and the commercial Roadway Worker Protection System (RWPS) (FCC ID 2AGO3-CM102, user manual at https://fccid.io/2AGO3-CM102/User-Manual/). The RWPS manual describes precisely the PAD/VAD/WDU architecture recited in this patent's specification. Metrom states it has been selling UWB safety systems to railroads since 2012 and claims deployment "on thousands of railway maintenance-of-way vehicles."
• Current status: Operating, actively litigating. Not acquired, not dissolved, no bankruptcy of record found. Continues to prosecute new applications (grants recorded in 2024 and 2025; four grants in 2025 per PlainPatent's PatentsView roll-up: https://plainpatent.com/company/metrom-rail-llc/).

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Assignment timeline

Only one recorded assignment exists on the public record for this patent. There is no post-issuance chain — that is itself the finding.

• Executed date not established / recorded 2017-06-30 — Reel/Frame not retrieved
  • Conveyance: Assignment (recorded as "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Richard Carlson; Marc Wayne Cygnus; Kurt Gunther; John Albert Plutt, Jr.; Peter Strezev; Sara Jo Woitel (all six joint inventors)
  • Assignee: METROM RAIL, LLC
  • Correspondent: Not retrieved. Could not be captured from any accessible source. This is a genuine evidence gap, not a negative finding — it should be pulled directly from Patent Assignment Search.
  • Context: Internal/original acquisition. Standard inventor-to-company assignment perfecting title in the operating company that employed the inventors. Not a fire-sale, not a reorg, not securitization, not a transfer to an asserter.

Source for the recording: Google Patents legal events for US 10,336,353 (2017-06-30 entry, "Assigned to METROM RAIL, LLC — reassignment," listing all six assignors), https://patents.google.com/patent/US10336353B2/en

No further assignments, security agreements, mergers, name changes, licenses, or releases are recorded against this patent. Google Patents lists Original Assignee = Metrom Rail LLC and Current Assignee = Metrom Rail LLC — i.e., title has never left the operating company.

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Timeline diagram

timeline
    title Ownership of US 10336353
    2016 : Priority date claimed
    2017 : Filed as application 15 623 996
         : Inventors assign to Metrom Rail LLC
    2019 : Patent US 10336353 granted
    2022 : Metrom sues Siemens and others
    2025 : Metrom sues Piper Networks
    2026 : Federal Circuit affirms invalidations

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NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. No transfer ever occurred. The sole recorded conveyance is inventor→Metrom Rail, LLC on 2017-06-30, and Google Patents still lists Metrom Rail, LLC as both original and current assignee. There is no "IP / Patents / Licensing / Holdings / Ventures" successor, no registered-agent address, and no single-purpose LLC anywhere in the chain.

2. Known asserter in the chain — NOT PRESENT. Metrom Rail, LLC does not appear on any of the referenced lists (Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, DGC, Spangenberg entities). It is the inverse of a listed asserter: it is the operating company being attacked by far larger players, through IPRs filed by Siemens Mobility, Hitachi Rail GTS (fka Ground Transportation Systems USA), Humatics, and Piper Networks in IPR2023-00468 / -00470 and IPR2024-00947 (https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1550914](/patent/1550914)).

3. Repeat correspondent across the chain — UNCLEAR / NOT ASSESSABLE. With only one assignment on record there is no recurrence to measure, and I could not retrieve the correspondent identity. For completeness (and not to be conflated with an assignment correspondent): Metrom's litigation counsel of record is McAndrews, Held & Malloy, Ltd. (Gregory C. Schodde; Rajendra A. Chiplunkar; Christian H. Hallerud), 500 W. Madison St., Chicago — appearing for Metrom in both the 2022 Delaware action and the 2025 MBTA/Piper action (see https://law.justia.com/cases/federal/appellate-courts/cafc/24-2223/24-2223-2026-05-11.html). That is plaintiff-side patent prosecution/litigation counsel for an operating company, not an NPE recording agent. Mark this signal unclear pending retrieval of the actual assignment cover sheet.

4. Cascading transfers — NOT PRESENT. Exactly one assignment in the entire patent's life, recorded 2017-06-30. Zero chained LLCs, zero shared-correspondent addresses, zero multiple-principal patterns.

5. Pre-litigation transfer — NOT PRESENT. The single assignment precedes the first infringement complaint (Metrom Rail, LLC v. Siemens Mobility, Inc., et al., No. 1:22-cv-00049-RGA, D. Del., filed 2022-01-13) by roughly 4.5 years. There is no 6-month sprint transfer into an asserting vehicle. The plaintiff/patentee is the same entity that has held title since 2017.

6. Bankruptcy fire-sale — NOT PRESENT. No Chapter 7/11 filing found for Metrom Rail, LLC. The company is a going concern: it continues to file (applications as recent as 2024, e.g. 18/921,581 published 2025) and to litigate.

7. Privateering — NOT PRESENT. Privateering requires transfer to an NPE that asserts on the operating company's behalf. Here the operating company asserts its own patents itself. Metrom's own press release frames the suits as protecting its own products: "Patents incent Metrom and other companies to develop the new, valuable products that in our case save lives…" (https://metrom-rail.com/filebin/Lawsuit/Metrom_Rail_Press_Release_1.18.22.pdf).

8. Defensive aggregator — NOT PRESENT. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. RPX and Unified both index this family, but as monitors/defendants, not owners: Unified Patents carries US 2019/0283787 A1 with "Parent Company: Metrom Rail LLC" (https://portal.unifiedpatents.com/patents/patent/US-20190283787-A1), and RPX hosts the D. Del. complaint as litigation intelligence (https://insight.rpxcorp.com/litigation_documents/14728170).

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Verdict

Operating-company assertion.

The record shows a single assignment — inventors to Metrom Rail, LLC, recorded 2017-06-30 — after which title has never moved; Google Patents lists Metrom Rail, LLC as both original and current assignee of US 10,336,353 with no security interests, name changes, or onward conveyances. Metrom is a genuine manufacturer that shipped the AURA CAS and Roadside Worker Protection System embodying this specification (FCC ID 2AGO3-CM102), continues to prosecute the same family (grants through 2025), and is itself the plaintiff asserting this patent family against named competitors Siemens Mobility, Hitachi Rail GTS, Humatics, Thales and Piper Networks starting with D. Del. 1:22-cv-00049-RGA filed 2022-01-13. Zero NPE signals fire; the only open item is the missing reel/frame and correspondent of record, which is a documentation gap rather than evidence of a shell chain. Note also that the parent of this application, US 10,179,595, is one of the five patents Metrom asserted in the January 2022 complaint, confirming this is a self-asserted operating-company portfolio.

Caveat on scope: I could not confirm that US 10,336,353 itself was named in a complaint. The January 2022 press release lists five asserted patents (10,778,363; 8,812,227; 9,043,131; 10,737,709; 10,179,595) and the amended complaint's claim charts refer to "the '363 patent," which is ambiguous as between US 10,778,363 and US 10,336,353. I am not resolving that ambiguity by inference; the '353 patent is nevertheless in the same specification family as patents that are being asserted by its owner.

Verify at: https://assignmentcenter.uspto.gov/patent/index.html — search "10336353" to pull the cover sheet and capture the reel/frame and correspondent fields missing from this report.

I'll search for the specific patent and its cited prior art references.

Let me retrieve the complete citation list for US 10,336,353 specifically.

I have the core citation list. Let me verify the foreign patent documents and non-patent literature for US 10,336,353, and get details on the key references.

US 10,336,353 B2 — Prior-Art / Cited-References Analysis

Scope note (important). Per your strict rule, I treated the number literally as 10,336,353 and did not substitute any sibling (e.g., 10,926,783, 10,737,709, 10,179,595). All references below come from the "References Cited" / "Patent Citations" data that appears on the face of US 10,336,353 as reported by Justia and Google Patents for that exact number. I was able to retrieve the bibliographic citation list, but I was not able to retrieve the full prosecution history / examiner's reasons-for-allowance for the '353 patent itself before hitting the tool limit, so the §102 "which claim" mapping below is analysis, clearly flagged as such, not a quotation of an examiner's rejection.

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A. What US 10,336,353 actually claims (mapping baseline)

• Claim 1 — the only independent claim I could obtain verbatim (via Justia's copy of publication US 2017/0282944 A1, which matured into the '353 grant): a system for worker protection comprising a wayside detection unit with (i) a housing, (ii) a support structure (e.g., tripod or permanent connection), (iii) a power supply, (iv) one or more sensory components for detecting/monitoring/tracking vehicles, (v) a communication component with one or more antennas, and (vi) one or more circuits to process signals/data and perform applications/functions.
  • Source: https://patents.justia.com/patent/20170282944 (claims 1–3 reproduced)
• The '353 grant carries 20 claims (per the prior summary section). The dependent claims add the tripod/permanent-connection support (cl. 2, seen), autonomous detect-and-track (cl. 3, seen), and further WDU/alert features.
• ⚠️ Flagged uncertainty (carried forward): the exact boundaries and any second independent claim of the granted '353 were not authoritatively confirmed. The "compact wearable personal alert device" grouping in the unity-of-invention document belongs to a different Metrom application (a 30-claim filing), not verified as the '353 — so do not treat the PAD claim as confirmed for the '353.

This matters because § 102 anticipation requires a single reference to disclose every element of a claim. Nearly all references on the '353 face are section-103-type art (teach pieces of the system), and only a few are plausible single-reference §102 candidates for claim 1.

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B. Complete cited-reference list (29 U.S. documents on the face of the '353)

Source for the list: Justia patent record for 10336353 (https://patents.justia.com/patent/10336353, "Referenced Cited") and Google Patents US10336353B2 ("Patent Citations (29)"). Dates are the printed issue/publication dates. Titles are given where confirmed from the source snippets; "[title not confirmed]" marks items whose full title I could not verify before the tool limit.

U.S. utility patents (21)

U.S. patent application publications (8)

Non-patent literature (NPL)

• "International Search Report and Written Opinion for PCT/US2016/023754, dated Aug. 8, 2016" (10 pages). This is the ISR/WO from the parent PCT (the Metrom worker-protection family). It is cited as NPL; its substantive prior-art citations (not separately enumerated on the '353 face in the sources I retrieved) are the references the ISA considered against the parent — a useful secondary lead, but not itself an anticipatory reference.

⚠️ Foreign patent documents: The Google Patents "Patent Citations" count for the '353 resolves to 29 U.S. documents, matching the 29-item U.S. list above. I did not find a "Foreign Patent Documents" block on the '353 face. (By contrast, the sibling US 10,737,709 cites foreign documents such as CN 1417071, CN 1676375, CN 102923158 — do not attribute those to the '353.) I could not confirm foreign-document citations for the '353 before the tool limit — treat the "none" as unverified.

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C. The most relevant prior art for §102 purposes (ranked)

Tier 1 — genuine single-reference §102 candidates for claim 1 (WDU system):

1. US 8,109,474 B2 — Bartek, "Dual ultrasonic train detector" (Feb. 7, 2012). Closest disclosure of a wayside-mounted detection unit with housing, sensors, and electronics. Confirm whether it discloses the recited support structure + power supply + communication component/antenna + circuits combination; if so, it is the strongest §102 anticipation of claim 1.
2. US 6,113,037 A — Pace, "Railroad maintenance-of-way personnel warning system apparatus and method therefor" (Sep. 5, 2000). Wayside equipment that warns track workers of trains — closest to the purpose of the '353.
3. US 2012/0296562 A1 — Carlson, "Collision avoidance system for rail line vehicles" (Nov. 22, 2012). Closest to the claimed system framework; already treated by an examiner in the family as teaching "a system for worker protection; a housing; antennas; circuits."

Tier 2 — strong §103 combinations against claim 1 and its dependents:

• US 8,786,428 B2 (Sheardown/Bombardier, "Track worker safety information system") + US 2013/0166114 A1 (Baines/Aurizon, "Worker Protection Method") + US 8,109,474 B2 (Bartek) — together supply wayside monitoring, worker alerting, and detection.
• US 5,620,155 A (Michalek) and US 5,554,982 A (Shirkey) supply the wireless wayside-triggered alert element.

Tier 3 — relevant only to a wearable/PAD-style claim (if one exists in the '353):

• US 2014/0045547 A1 (Singamsetty, wearable communication device), US 5,652,570 A (Lepkofker, individual location system), US 8,248,263 B2 (Shervey), US 7,167,082 B2 (Stigall).

Tier 4 — background only (no §102/§103 force against the '353 claims): US 2,475,578; US 2,762,913; US 5,198,800; US 5,939,986; US 6,208,260; US 6,232,887; US 6,650,242; US 6,145,792; US 5,727,758; US 5,924,651; US 8,952,805; US 8,344,877; US 2010/0102954; US 2011/0006912; US 2011/0152971.

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D. Cross-check against the previously generated section (contradiction check)

• ✅ No contradiction with the prior summary's finding that no 2026 CAFC docket and no IPR petition names 10,336,353. The IPR cluster (IPR2023‑00439/‑00452/‑00460/‑00468/‑00470) and the Metrom Rail v. Siemens Mobility appeal concern other Metrom numbers (e.g., 9,043,131 / 8,812,227 / 10,179,595 / 10,737,709 / 10,778,363), not the '353.
• ⚠️ One correction/refinement to the prior section: the earlier section said it could not confirm the second independent claim and inferred a "compact wearable personal alert device" claim. The unity-of-invention document I re-encountered (Group I claims 1–20 = compact wearable PAD; Group II claims 21–26 = vehicle-mounted alert device; Group III claims 27–30 = wayside detection unit) is from a different, 30-claim Metrom application — it cannot be used to infer the '353's claim set. The '353's confirmed independent claim 1 is the wayside detection unit system. Treat the PAD claim inference as unverified for the '353 specifically.
• ⚠️ Useful new datum: the same unity document shows an examiner expressly citing US 2012/0296562 A1 (Carlson) as teaching "a system for worker protection (Para. 25); a housing (Para. 40); one or more antennas…(Para. 28); one or more circuits…(Para. 49)," which corroborates Tier‑1 relevance of that reference for the system framework.

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E. Caveats (stated explicitly)

1. "Cited" ≠ "applied." The 29 documents above are what appears on the patent's face (examiner citations + applicant IDS). I did not retrieve the '353's examination record, so I cannot state which were used in an actual §102 rejection vs. a §103 combination vs. merely listed. The §102 "which claim" column is my reasoned mapping, not an examiner's.
2. No full claim set confirmed. Only claim 1 (and dependents 2–3) of the '353 were verifiable. Any single-reference anticipation assertion should be re-run once the granted claim sheet (USPTO PatentCenter / the grant PDF) is obtained.
3. Dates are the printed patent/publication dates as reported by Justia/Google Patents; I did not independently verify each against the original documents before the tool limit.
4. Foreign documents: absence of a foreign-citation block on the '353 is unverified; the CN documents (CN 1417071, CN 1676375, CN 102923158) that surfaced in searches belong to the sibling US 10,737,709, not to the '353, and I did not attribute them to it.

If you can lift the tool limit by one call, the highest-value next step is to pull the grant PDF of US 10,336,353 to lock the full 20-claim set and a PatentCenter "References Cited"/IDS list to confirm whether any foreign documents or additional NPL were cited.

I'll work from the patent text provided and search for the actual prior-art references relevant to this patent, since the "Prior Art" section content wasn't carried into this message.

Good — I've now surfaced the actual prior-art references cited on the '353 patent and, more usefully, the art asserted in the IPRs against the closely related sibling patent. Let me pin down the key references (Cross, Meyer, Grisham) precisely.

Obviousness Analysis — US 10,336,353 B2 ("Worker Protection System") under 35 U.S.C. § 103

Analyst note on the record used. The message states to use "the results from the Prior Art section of this page," but that section's content was not carried into this prompt — only the Patent summary and Litigation summary from the prior run were supplied. Rather than improvise, I reconstructed the prior‑art record from the authoritative sources actually on the Google Patents page (the "Patent Citations (29)," "Similar Documents," and "Cited By" lists) and — more importantly — from the Petitioners' invalidity record for the closely related sibling patent US 10,737,709 ("the '709 patent"), which is in the same Metrom Rail family (same specification lineage, same inventors). Where I rely on that sibling‑patent record I flag it explicitly, because it is evidence of what a POSITA finds obvious, not a finding that the '353 claims have been adjudicated obvious. I do not represent that any tribunal has ruled on the '353 patent itself.

I will also flag at the outset the constraints from the earlier sections: only claim 1 of the '353 patent was obtained verbatim; the remaining independent‑claim boundaries were inferred. That limits how precisely I can scope the dependent claims, and I treat those inferences as such.

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1. The § 103 critical date — which art qualifies

This is the gating question, and the '353 patent's continuity makes it non‑trivial:

Because this is a post‑AIA application (filed 2017), AIA § 102/103 governs. The effective filing date of a given claim is the earliest date to which that claim's subject matter is entitled. Two consequences:

1. A claim gets benefit only for subject matter actually supported by the parent. To the extent the '353's claims recite material that is new matter relative to 15/078,427 (e.g., the wayside‑detection‑unit framing), the critical date slides forward — at best to the 2016‑06‑15 provisional (62/350,520) and otherwise toward the 2017‑06‑15 filing date. This widens the prior‑art window.
2. The '595's own publication (US 2016/0280240 A1, pub. 2016‑09‑29) is by the identical inventive entity and same owner (Metrom Rail), so it is excepted from being § 102(a)(2) art under § 102(b)(2)(A)/(C) (same inventors / common ownership). I therefore do not rely on the family's own publications as art. That matters because a naïve searcher might try to use Metrom's own earlier '595 publication against the '353 — that move fails on the common‑ownership/inventor exception.

Practical result: the '353 claims are presumptively measured from 2016‑03‑23 (giving the patent its best case). All references below either pre‑date that date on their own faces, or have earlier published counterparts that do.

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2. Person of ordinary skill in the art (POSITA)

Drawing on the '353's field and the IPR record's framing: a POSITA is a person with a bachelor's degree in electrical/computer engineering (or equivalent) and ~2–3 years' experience in railway signaling, positive‑train‑control (PTC), or wayside/vehicle proximity‑warning systems, or a comparable combination of education and experience. That artisan would be familiar with: GNSS positioning; RF/CDMA/UWB radio ranging; worker‑worn alert hardware (vibration/audible/LED indicators, acknowledgment buttons); inductive (wireless) charging; NFC/RFID for configuration; and FRA/AREMA worker‑protection practice (e.g., 15‑second warning norms cited in the '353 spec).

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3. The principal prior‑art references

Two housekeeping points the reader should not miss:

• The Metrom IPR record (ex parte view). Petitioners challenging the sibling '709 patent ran grounds captioned "Ground 1: Meyer–Grisham," "Ground 2: Cross–Grisham," and "Ground 1E: Cross + Cook." Those are real, documented POSITA combinations in this exact technical space. They are evidence of the level of ordinary skill and of what an artisan would combine — but they are directed at the '709's UWB‑specific claims, not at the '353. I use them as motivation‑to‑combine scaffolding, not as an adjudication of the '353.
• The '353 appears broader than the '709. Claim 1 of the '353 (see prior summary, verbatim from RPX) recites a wayside detection unit without requiring UWB. That makes the broad‑claim obviousness case easier here than in the '709 IPRs, because the UWB narrowing limitation is absent.

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4. Claim construction of independent claim 1 (WDU‑centric) and the inferred second independent claim

Claim 1 (verbatim core). "A system for worker protection, the system comprises: a wayside detection unit, configured for placement on or near path of a vehicle… wherein the wayside detection unit is configured to communicate signals and/or messages to one or more companion alert devices while providing monitoring and tracking services in a work site." Distilled functional elements (from the prior run and the spec's WDU description, FIG. 4):
(a) housing enclosing components; (b) support structure (e.g., tripod); (c) power supply (integrated/rechargeable); (d) sensory component(s) to detect/monitor/track the vehicle (visual, IR, laser ranging, etc.); (e) communication component with one or more antennas; (f) one or more circuits to process signals/data and perform applications/functions; configured to communicate with companion alert devices.

Second independent claim (inferred). A compact wearable personal alert device with an attachment structure (clip/strap/arm‑band), configured to receive signals from a companion alert device, generate a safety alert, and output visual/audio/tactile indications. (Inference flagged again — verify against the granted claim sheet.)

Third independent claim group (inferred from the family's unity‑of‑invention statement). A vehicle‑mounted alert device that broadcasts alert‑triggering signals, generates alert data, and outputs operator feedback. (The prior run confirmed the family's Group I/II/III split as PAD / VAD / WDU.)

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5. Element‑by‑element obviousness — independent claim 1 (WDU system)

Ground 1A (primary): Cross alone, or Cross in view of Bartek.

Motivation to combine (Ground 1A). Cross and Bartek are in the same field of endeavor (wayside rail‑safety detection) and address the same problem ("warn workers of trains; detect trains at the wayside"). KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), teaches that where a known technique (a wayside train detector with sensors/housing/support/mast) is used to improve a similar device in the same way (adding autonomous detection to Cross's signal‑forwarding priority detector), the combination is obvious. The '353's own specification supplies the motivation: it expressly contemplates the WDU "used when no VADs are being used," i.e., a standalone wayside unit that must autonomously detect the train — exactly the gap Bartek fills. There is no teaching away.

Reasonable expectation of success. Both are mature, off‑the‑shelf rail technologies; mounting a sensor head on a mast/tripod with a radio and a battery is routine.

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6. Obviousness — the inferred wearable‑PAD independent claim

Ground 1B: Cross (+ Cook for the sealed/inductively charged PAD).

• "compact wearable personal alert device … attachment structure" → Cross's PNU: "a simple hardware device" that "attaches to a worker using a clip" ([044], FIG. 2). If the claim recites a strap/arm‑band alternative, that is a predictable substitution of a known fastening mechanism (a wrist strap for a wearable) with no unexpected result — the '353 itself presents clip/strap/arm‑band as equivalents.
• "generate, in response to signals received from a companion alert device, a safety alert" → Cross: PNU receives AVL packets and "determine[s] whether a warning signal needs to be transmitted" ([019], [038]).
• "output … visual/audio/tactile indications" → Cross PNU "emit[s] a warning sound"; Cross's spec also describes vibration and visual cues; Penza US 5,727,758 teaches tactile+audible worker warnings. Any of the three indicator modalities is expressly old.
• Confirmation/acknowledgement (likely dependent claim) → Meyer (near‑range acknowledgement button/signal) and/or Cross's signalling back to the VCU.
• Sealed, no‑connector PAD with inductive charging (a likely dependent claim) → Cook US 2009/0243397 A1, whose teaching of a rechargeable‑without‑direct‑connection, sealed device was the basis of "Ground 1E: Cross + Cook" in the sibling IPR. Motivation: sealing a wearable against rail‑work environments (rain, dust, ESD) while enabling wireless recharge — a predictable, well‑understood substitution (inductive charging coil for a connector).
• GNSS in the PAD (likely dependent) → Cross's PNU is "capable of receiving GPS" ([041]); Cross teaches using satellite positioning to determine worker location; JP 4785031 likewise uses GNSS in the worker device.

Motivation. Single‑reference Cross anticipates/renders most of the PAD claim; Cook is applied only for the charging/sealing feature, and KSR endorses combining a secondary reference that improves a known device in a known way (wireless charging to enable sealing) at a low marginal cost.

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7. Obviousness — the inferred vehicle‑mounted (VAD) independent claim

Ground 1C: Cross (+ Meyer for the operator feedback/acknowledgement loop).

• "vehicle‑mounted alert device … broadcast alert triggering signals" → Cross's VCU, an "onboard unit," permanently or temporarily mountable, that transmits AVL packets/alerts.
• "generate data relating to alerts and/or other devices … output feedback to the operator" → Cross's VCU "real‑time monitoring and display of worker activity and locations on a user interface" (tablet) and "logs and reports"; Meyer adds the "not all personnel acknowledged" collision‑status display to the operator.
• Operator acknowledgement of the alarm / silencing → Cross and Meyer.

Motivation. Both references address warning the operator and confirming worker receipt; combining a vehicle computer unit (Cross) with Meyer's acknowledgement‑based collision‑status logic yields predictable, beneficial results (operator knows whether the work zone is clear).

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8. Representative dependent claims — obviousness snapshots

(Statuses per the family unity statement; exact numbers to be verified.)

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9. The global motivation‑to‑combine rationale (why an artisan would combine)

Independent of any single reference pairing, five KSR‑recognized rationales run through the whole analysis:

1. Common field, common problem. R1–R10 all address warning track workers of approaching trains (B61L 23/06 — the '353's own primary class). Same field is the strongest combination rationale.
2. Predictable use of a known technique to improve a similar device. Adding autonomous sensing (Bartek) to a wayside unit (Cross); adding UWB ranging (Grisham) or GPS for distance/speed; adding inductive charging (Cook) to enable sealing.
3. Design incentive / market and safety pressure. The '353's specification itself cites a 15‑second line‑of‑sight warning norm and notes redundancy (WDU used with or without VADs), which supplies the very motivations (redundant, longer‑range warning; standalone operation) an artisan would act on.
4. Flexibility of implementation. Cross expressly contemplates temporary or permanent mounting and tablet/phone interfaces — i.e., the reference itself invites the portable/distributed variants the '353 claims.
5. No teaching away, no unexpected results. Each added feature (sensor head, tripod, wireless charging, GNSS, acknowledgement) performs its known function with predictable results; nothing in the cited art discourages the combinations.

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10. Rebuttal considerations (what would have to be overcome / what is genuinely open)

• Secondary considerations (§ 103 objective indicia). I found no evidence of record tying any objective indicia (long‑felt need, unexpected results, commercial success with nexus, copying, industry praise) to the claimed subject matter of the '353. If Metrom wants to defend, it would need a nexus between the claims and any such evidence. The family's heavy litigation (Siemens, Hitachi/GTS, Piper/MBTA) is not itself evidence of non‑obviousness. Gap flagged: I could not retrieve a prosecution history or expert record for the '353 specifically; the strongest counters likely lie in the file wrapper (e.g., whether the examiner allowed claim 1 over the cited art, and on what basis).
• Priority-date exposure. If any independent claim relies on new matter added in the '353 CIP (e.g., the WDU framing), its effective date slides toward 2016‑06‑15/2017‑06‑15, which pulls additional intervening art into play. Conversely, if Metrom proves full support back to 2015‑03‑23, some 2015–2016 art drops out. The single most consequential factual dispute is therefore what subject matter the '353 claims are actually entitled to.
• Same‑family self‑art is unavailable to challengers. US 2016/0280240 A1 (the '595 publication) is by the same inventors/owner and is excepted under § 102(b)(2)(A)/(C). A challenger should not build a § 102/§ 103 case on Metrom's own prior publications.

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11. Bottom line

• Claim 1 (WDU‑centric system) is, on the available record, highly vulnerable to a § 103 challenge over Cross (US 2014/0104081 / US 9,542,852) in view of a wayside‑detector reference such as Bartek (US 8,109,474 / US 7,624,952) — different field entrants that are actually in the same field. The '353's own specification supplies the motivation (standalone WDU operation) and the claim language is broad and largely functional.
• The inferred PAD independent claim is vulnerable over Cross alone, with Cook (US 2009/0243397 A1) supplying the sealed/inductively‑charged limitation and Meyer supplying acknowledgement.
• The inferred VAD independent claim is vulnerable over Cross in view of Meyer.
• Dependent claims directed to indicators, attachment structures, acknowledgement, GNSS, logging, relaying, NFC re‑configuration, power management, and diversity antennas each map to known techniques or to the '353's own face art.
• The strongest non‑obviousness arguments for Metrom are (i) proof of entitlement to the earliest priority (shrinking the art), and (ii) any secondary considerations with a proven nexus — neither of which appears in the record I could retrieve.

Confidence and gaps. High confidence in the reference identities for Cross (US 9,542,852 / US 2014/0104081), Cook (US 2009/0243397 A1), Bartek, Bombardier, Aurizon, Penza and JP 4785031 (all verified against the '353's own citation lists or the IPR record). Lower confidence on the exact bibliographic numbers for "Meyer" and "Grisham," which I could identify only as they are characterized in the Metrom IPR petitions (Meyer = a paragraph‑numbered worker‑protection application with mobile transponders/acknowledgement; Grisham = a UWB impulse‑radio disclosure). I have deliberately not invented numbers for them; they should be confirmed from petition exhibits IPR‑series 1550883/1550904 before being cited in any paper. Finally, note again the cross‑check mismatch: the prior Patent/Litigation sections ran with a stated "2026‑10‑01" date while this task sets the date to 2026‑04‑26 — it does not change the analysis, but the reader should be aware of the inconsistency.

If useful, I can (a) pull the full 20‑claim sheet of the '353 to lock the independent‑claim text I have inferred, and (b) resolve the exact numbers for Meyer and Grisham from the IPR exhibit index.