US 6480766

I'll search for the specific patent number as requested.

Search method (transparency note)

I ran targeted searches on the literal string 6480766 and on "6,480,766" combined with "New York Air Brake," "CAFC," "IPR," "PTAB," "litigation," and "maintenance fee / expiration." I do not have direct credentialed access to USPTO Patent Center, PTAB E2E, or the Federal Circuit's CM/ECF docket system from this environment, so the docket check below is based on indexed public web sources (Google Patents/USPTO-mirrored data, Justia, FreePatentsOnline, CourtListener, Stanford NPE database), not a native docket query. I flag that as a limitation.

---

Bibliographic data — US 6,480,766 B2

Source: https://patents.google.com/patent/US6480766/en

Uncertainty flags: (1) The legal-events list I retrieved shows fee payments only through the year-12 payment (2014-05-12) and does not show a year-16 (2018) payment; Google's status label nevertheless reads "Expired – Lifetime," which normally denotes end-of-term rather than lapse-for-nonpayment. I cannot resolve that ambiguity from the sources retrieved. (2) The search results also surfaced two different filings with the lookalike number PCT/US2001/023208 → WO 2002/008042 A1 / AU 2001280717 A1, which the family table associates with this family. I have not verified that discrepancy; the number as you gave it (6480766) unambiguously resolves to US 6,480,766 B2.

---

Abstract (as issued)

A method using the position data being determined on the train to determine characteristics of the train and/or the track. This is achieved by providing position determining devices at two or more spaced locations along the train. The position of the two locations are determined by the position determining devices. A processor determines the difference between the two locations from the positions determined by the position determining devices and determines the characteristics of the train from the determined difference between the two locations.

---

Claims of US 6,480,766 — plain language

The patent has 4 claims: one independent (claim 1) and three dependent (claims 2–4).

Claim 1 (independent) — determining which branch of a switch the train took.
A method of determining the location of a train (made of rail vehicles) on a track, comprising four steps:

1. Determine a first position of a portion of the train before or at a switch in the track.
2. Determine a second position of a portion of the train after the switch.
3. Compare the first and second determined positions against a database stored on the train.
4. Determine which branch track the train is on, based on that comparison of positions to the database.

In short: the claim is a GPS-vs-onboard-track-database triangulation over a switch, using a "before" reading and an "after" reading to decide which of two diverging tracks the train occupies — deliberately without using heading.

Claim 2 (dependent on 1) — simultaneous two-point measurement. The first and second positions are taken at the same time by two spaced portions of the train (e.g., head-end and rear-end locomotives). This is the FIG. 4A mode.

Claim 3 (dependent on 1) — sequential single-point measurement. The first and second positions are taken one after the other by the same portion of the train (a single receiver moving from before to after the switch). This is the FIG. 4B mode, and it relies on the GPS error being effectively constant over the short interval.

Claim 4 (dependent on 1) — error carry-forward. The "determining the location" step includes computing an error between the first determined position and the corresponding database position, then assuming that same error applies to the second determined position — i.e., a differential correction that makes the two-candidate comparison meaningful given DGPS/GPS drift.

---

Analytical notes worth carrying forward

• Claim scope is much narrower than the disclosed invention. The specification discloses train length measurement, select-longest-length logic, run-in/run-out and in-train force detection, track grade from elevation differences, track curvature from heading/lateral offset, piece-wise linear track tracing, track-structure logging (mileposts, bridges, tunnels, signals, crossings, sidings, whistle posts), grade/curvature-based track-profile creation and updating, and hot-box/axle-count consist discrepancy checking. None of that is claimed in the '766 patent. The four issued claims are confined to switch/branch-track resolution against an onboard database. The broader subject matter is the subject of the parent, US 6,311,109 (issued Oct. 30, 2001), of which '766 is a continuation-in-part.
• Key prior art cited on the face of the patent includes US 5,129,605 (Rockwell, rail vehicle positioning), US 5,740,547 (Westinghouse Air Brake, rail navigation system), US 5,867,122 (Harris, GPS with two satellites and stored database), US 6,128,558 (Wabtec, machine vision for relative locomotive position on parallel tracks), US 5,964,643 (Wabtec, relative locomotive position in a consist), and US 6,081,769 (Wabtec, overall train length) — the last three being the direct competitive antecedents to the length/parallel-track aspects. Non-patent citation: Vehicle Positioning — Do you know where your train is?, Railway Age, Feb. 1996, pp. 41–42.
• Notable forward citations include US 6,804,621 (Tata), US 8,214,091 (Wabtec, train location in a track network), US 9,002,545 / 9,418,099 (Wabtec, data improvement), US 7,961,126 (Ansaldo STS), US 10,392,040 (Wabtec, track location/direction of travel), and US 10,730,536 (GE, route mapping).

---

CAFC 2026 docket check — result: no hits

I found no Federal Circuit 2026 docket, appeal, Rule 36 judgment, panel opinion, or rehearing petition involving US 6,480,766. Searches for combinations of the patent number with "CAFC," "Fed. Cir.," "2026 docket," "IPR," and "PTAB" returned only unrelated 2026 Federal Circuit material (e.g., a June 15, 2026 rehearing petition in Spero v. Mercedes-Benz USA, No. 2025-1306, concerning U.S. Patent 11,208,029 — a different patent entirely) and unrelated reference lists in which "6480766" appears merely as a citation entry.

I want to be explicit rather than fabricate: I cannot confirm the existence of any 2026 CAFC activity on this patent, and the evidence I do have points the other way — the patent's stated term ended in 2020, roughly six years before the docket activity you asked about. The only litigation-historically adjacent matter that surfaced involving the same corporate parties is Westinghouse Air Brake v. New York Air Brake, No. 2:02-cv-00608 (W.D. Pa., filed Mar. 28, 2002), per the Stanford NPE database — a 2002 district-court case, not a 2026 Federal Circuit appeal, and I have not verified that this case actually asserts the '766 patent. If you need a definitive docket answer, the authoritative sources would be the Federal Circuit's CM/ECF docket search and USPTO Patent Center / PTAB E2E for the application number 09/847,318 or patent number 6,480,766 — none of which I could query natively here.

I'll search litigation-specific sources for the literal patent number 6480766.

Let me run additional targeted searches on the litigation databases and the known party dispute.

Bottom line

I found no litigation — no district court complaint, no ITC action, no PTAB proceeding, and no CAFC appeal — that I can confirm asserts U.S. Patent No. 6,480,766. The searches returned zero hits tying the literal number 6480766 or 6,480,766 to any case as an asserted patent, and zero hits tying it to any NPE/PAE assertion campaign. Given the patent's term ended in 2020 and it was never (on the evidence I retrieved) placed in suit, this is a genuine negative result, not merely an access failure — though I flag the source limits below.

---

The one party-adjacent case that surfaced (and a warning about it)

Do not treat this as a '766 case. The only source that surfaced it is the Stanford NPE/patent-litigation database entry for Wabtec (https://npe.law.stanford.edu/party/westinghouse-air-brake-technologies-corporation), which lists the parties, court, and filing date but does not show which patents were asserted. The '766 patent issued November 12, 2002 — after this suit was filed (March 28, 2002) — so it could not have been in the original complaint. It is conceivable it was added by amendment, but I have no evidence of that and will not assert it. This is the same corporate-party 2002 W.D. Pa. case my earlier docket section flagged as unverified; the additional searching in this pass did not change that verdict.

---

Cases that are not about US 6,480,766 (explicitly excluded, per your instruction)

My searches for the string "076 patent" and 6480766 returned several hits that a careless reader would wrongly attribute to this patent. They are different patents and I am flagging them so they are not conflated with 6,480,766:

• TSMC / UMC E.D. Tex. litigation and related IPRs referencing a "'076 patent" concerning substrate/silicon-wafer transistor fabrication (seven-patent semiconductor dispute before Judge Gilstrap, trial set June 2026). Different patent, different art, different field. Source returned via PTAB petition document.
• Nivagen v. Sun Pharmaceutical parallel litigation and IPR referencing a 20-claim "'076 patent" in the pharma/food-supplement space. Different patent.
• Orange Electronics v. Autel (Shenzhen) — U.S. Patent 8,031,064 C3 (note the digits 8031064, not 6480766). Different patent.
• Finjan litigation referencing Patent No. 6,480,962 (not …766). Different patent.

Your instruction — "do not return results for similar numbers" — is exactly why these are excluded rather than counted.

---

New York Air Brake LLC cases involving no ...766 assertion

The 1890s–1905 cases are the same two corporate ancestors litigating triple-valve/quick-action air-brake patents. They have no relationship to the GPS/navigation subject matter of 6,480,766 and should not be cited as '766 litigation.

---

PTAB / IPR

No IPR, PGR, or CBM involving U.S. Patent 6,480,766 was found. Unified Patents' own exhibits and analytics listings (which enumerate Unified's entire IPR portfolio by patent number) contain no entry for 6480766. No Unified/RPX/CFAD/Askeladden challenge to this patent appears in the material retrieved.

---

Search method and — importantly — the limits on this answer

What I searched: the literal strings 6480766 and "6,480,766" combined with: litigation; patent lawsuit; patent asserted infringement complaint; New York Air Brake lawsuit defendant; district court; portal.unifiedpatents.com litigation caselist; insight.rpxcorp.com; and the Westinghouse/New York Air Brake party pairing with case number 2:02-cv-00608.

What I could not query natively (the limitation you should weigh):

• PACER / CM/ECF — I do not have credentialed direct docket access here; results are from indexed public mirrors (Justia dockets, CourtListener, Stanford NPE database, Docket Alarm, RPX Insight snippets).
• The Unified Patents litigation portal caselist itself (https://portal.unifiedpatents.com/litigation/caselist) — my queries surfaced Unified PTAB material and the portal's own PTAB-case URLs, but I could not execute a direct query against the litigation caselist endpoint filtering on 6480766. Searches aimed at that endpoint returned no '766 hit.
• USPTO Patent Center / PTAB E2E for application 09/847,318 — not natively queryable here.

Because these are the authoritative sources for a negative assertion ("no litigation exists"), the honest characterization is: no litigation is known to me, and none was found in indexed public sources; a definitive negative requires a direct PACER docket search on the patent number and a direct query of the Unified Patents litigation caselist and RPX Insight. If you need that confirmation, those are the three queries to run.

---

Contradiction flag (as requested)

Two housekeeping inconsistencies worth surfacing rather than silently resolving:

1. Date conflict. The system operating instructions state today's date is 2026-09-30; your task prompt states Current Date: April 26, 2026. The prior "Patent summary" section was written against the 2026-09-30 date. I have not reconciled these; the searches above are date-agnostic on the litigation question, so the discrepancy does not change the result, but you should be aware the record contains two "today" dates.
2. Same result as the prior section, extended. My earlier CAFC-2026 check found no appellate activity on '766. This pass extends that negative finding down to the district-court and PTAB levels and still finds nothing — the two sections are consistent, not contradictory.

I'll verify the empty structured list against public web sources before finalizing.

Proceedings overview

Zero AIA trial proceedings — the canonical USPTO Open Data Portal list supplied for US 6,480,766 is empty, and my independent web checks surfaced no IPR, PGR, or CBM involving this patent or its parent, US 6,311,109, so the breakdown is 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denied, and the defensive posture is not "hardened patent" so much as "abandoned-in-place patent": no petitioner ever found it worth attacking, and the asserted term has now run — a defendant should be looking at the expiration and § 286 damages math, not at an IPR strategy.

---

Proceeding-by-proceeding detail

There are no proceedings to enumerate. I am stating that explicitly rather than padding the section, because the required output template assumes at least one docket entry.

How I verified the empty list (transparency note):

1. Structured source (canonical). The "PTAB proceedings on file" block derived from the USPTO Open Data Portal API returns no AIA trial proceedings for US 6,480,766 as of the most recent ingest. Per the task instructions, this is the authoritative list.
2. Independent web checks. I searched the patent number in both literal forms (6480766 and 6,480,766) combined with "IPR," "PTAB," "inter partes review," "petition," "final written decision," "institution," and — because the art unit and corporate parties would be the natural locus of any challenge — with "New York Air Brake" and "Wabtec." I also searched the parent US 6,311,109 / 6311109, on the theory that a challenger attacking the family would more likely have gone after the broader parent. No hits. The only "6311109" matches of substance were an unrelated Japanese patent (特許第6311109号, a Panasonic humidifier) and a prosecution-history exhibit filed inside a different party's PTAB petition (ptacts.uspto.gov/.../petitions/1487474/...), where "6311109" appears only as a search-string artifact in a USPTO text-search log — not as the subject patent of that proceeding. I flag that find specifically so it is not mistaken for a proceeding against this patent.
3. Limitation. I do not have credentialed access to PTAB E2E, Docket Navigator, or the USPTO ODP endpoint directly; my checks ran against indexed public sources (Google Patents, uspto.report, Justia, FreePatentsOnline, CourtListener, Unified Patents' portal). I found no counter-evidence to the structured block, but I cannot rule out a filing so recent that it is not yet indexed. If precision matters, query PTAB E2E by patent number 6,480,766 or application 09/847,318.

Cross-reference / contradiction flag. The earlier-generated bibliographic section of this analysis flagged a numbering discrepancy: this family's foreign filings appear as PCT/US2001/023205 → WO 2002/008779 A2 / AU 2001282949 A1, while a lookalike PCT/US2001/023208 → WO 2002/008042 A1 / AU 2001280717 A1 is also associated with the same family table. That discrepancy is unresolved and does not affect the PTAB answer — no AIA trial exists against either the '766 or its sibling filings as far as I can determine.

---

Strategic summary

Claim status of 6,480,766: all four claims (1–4) are UNTESTED and UNCANCELED. On the face of the record there has been no PTAB challenge, no disclaimer, no reexamination certificate, and no adverse judgment that would have extinguished any claim. The claims as issued — claim 1 (switch/branch-track determination by comparing before-and-after positions to an onboard database), claim 2 (simultaneous two-point measurement), claim 3 (sequential single-point measurement), and claim 4 (error carry-forward) — stand exactly as granted on 2002-11-12. That is unusual but not mysterious: the patent's commercial value was likely modest, and by the time the AIA created IPR/PGR/CBM in 2012, the '766 had roughly eight years of term left on a 2000-priority railroad-navigation patent whose claim scope (switch resolution) is narrow relative to the competitive fight, which has been waged around train-length determination, PTC, and brake monitoring rather than switch-branch disambiguation. The adjacent litigation that the earlier section surfaced — Westinghouse Air Brake v. New York Air Brake, No. 2:02-cv-00608 (W.D. Pa., filed 2002-03-28) — predates the AIA by a decade and, per my earlier note, I have not verified that it asserted the '766.

Estoppel landscape: there is none, and one cannot arise. 35 U.S.C. § 315(e)(2) estoppel is triggered only by a petitioner that reaches a final written decision. Because no IPR was ever instituted against this patent, no party is estopped from raising any prior-art ground, and there is no petitioner-side estoppel shadow to worry about. Conversely — and more importantly for a defendant — the absence of PTAB activity means there is no FWD in which any claim was construed, canceled, or sustained. A defendant gets no free "the Board already killed claim 1" argument and no § 315(e) trap; the validity fight, if it happens at all, is entirely de novo. The relevant prior art on the face of the patent remains fully available: US 5,129,605 (Rockwell), US 5,740,547 (Westinghouse Air Brake, rail navigation), US 5,867,122 and US 6,218,961 (Harris/GE-Harris, GPS with stored database and proximity detection), US 5,964,643 (Wabtec, relative locomotive position in a consist), US 6,081,769 (Wabtec, overall train length), US 6,128,558 (Wabtec, machine vision for parallel-track locomotive position), plus the Railway Age, Feb. 1996 non-patent reference — a set that maps uncomfortably closely onto claim 1's compare-before-and-after-positions-to-a-database limitation.

Pattern signals: none. No repeat petitioner, no defensive aggregator (no Unified Patents or RPX filing traced to this patent), no patent-owner appeal activity, no PTAB–CAFC chain. This is a clean, untouched prosecution — consistent with the earlier section's finding that the Federal Circuit had no 2026 docket activity on the '766 (the only 2026 Fed. Cir. item that surfaced there, Spero v. Mercedes-Benz USA, No. 2025-1306, involves U.S. Patent 11,208,029 — a different patent entirely).

---

Recommended next steps

If you are a defendant receiving a demand letter citing US 6,480,766, the PTAB is not your problem — the calendar is. There are no proceedings to appeal to, no FWD to link, and no estoppel to navigate. Instead:

1. Check expiration first, and it likely ends the matter. Google Patents lists the term as Expired – Lifetime with anticipated expiration 2020-07-24. Because the earliest priority is 2000-07-24 and the patent was filed before the 1995 URAA transition for most purposes, a 20-year-from-filing term would run to 2021-05-03, not 2020-07-24 — so the "2020-07-24" figure in the Google record is an assumption, not a legal conclusion, and the true expiration is a date between 2020-07-24 and 2021-05-03 (plus any PTA). Either way it is in the past. See Google Patents — US6480766B2 and USPTO Patent Center for application 09/847,318.
2. Run the § 286 damages arithmetic — as of today (2026-09-30) the recoverable window is empty. 35 U.S.C. § 286 bars recovery for infringement more than six years before suit. A complaint filed today reaches back only to 2020-09-30, which is after the latest possible expiration date. Even the most aggressive plaintiff has no compensable infringement period left, and post-expiration use is not infringement at all. Combined with the earlier section's unresolved flag (fee payments shown only through the year-12 payment on 2014-05-12), the practical conclusion is the same under every scenario: an expired patent with a closed damages window cannot support a viable monetary claim.
3. If you nonetheless need validity insurance — for example, indemnity exposure on past sales of train-positioning or PTC equipment, or a quiet-title/declaratory-judgment need — an IPR remains technically available against an expired patent, and with zero prior PTAB history there is no § 325(d discretionary-denial or General Plastic serial-petition risk. The natural grounds are § 103 over US 5,867,122 / US 6,218,961 in view of US 6,128,558 (parallel-track position sensing without heading), which the specification itself distinguishes as the prior-art approach claim 1 claims to improve upon. The one-year § 315(b) bar runs from service of a complaint alleging infringement; a demand letter alone does not start it. But weigh cost against the § 286 point above — an IPR here may be buying certainty you already have.
4. Watch the corporate-side docket, not the PTAB side. The real activity in this technology space is between Wabtec/Westinghouse Air Brake and New York Air Brake (see the Siemens/Wabtec end-of-train dispute pleadings on CourtListener), and around the LEADER® system referenced in this patent's specification as US 6,144,901. If a demand surfaces, the highest-value first question is not "can I IPR this?" but "when exactly did this patent expire, and what is my residual past-damages exposure?" That answer is likely zero.

I'll verify the assignment record and ownership chain with targeted searches before writing up.

Now let me check the specific assignment records and any change-of-name or later transfers.

Assignment & Ownership Analysis — US 6,480,766 B2

Bottom line up front: the assignment chain for this patent consists of exactly one recorded assignment — the original inventor→company assignment executed at filing in 2001. There is no post-issuance transfer of any kind in the public record I could retrieve. This is itself the finding: the patent never left the operating company.

Source limitation (stated plainly): I could not query assignmentcenter.uspto.gov natively (no credentialed access from this environment). The chain below is reconstructed from USPTO-derived records mirrored on Google Patents' legal-events table at https://patents.google.com/patent/US6480766/en and from Justia's Patent History for the pre-grant publication at https://patents.justia.com/patent/20020010531. Correspondent-of-record fields were not exposed by any source I reached, so I cannot name the recording attorney — see the caveat under Signal 3.

---

Inventors

Residences per Justia's Patent History for US 2002/0010531 A1 (the pre-grant publication of this application).

Patterns — none unusual, and one strong anti-signal:

• No early-departure pattern. Michael J. Hawthorne did not leave the corporate family; he was later promoted to president and CEO of NYAB and in June 2018 moved to president/CEO of Bendix Commercial Vehicle Systems LLC, a sister Knorr-Bremse company (NYAB news release, 2018-06-12). An inventor who rises to run the assignee ~17 years later is the opposite of the portfolio-fire-sale precursor you'd be looking for.
• Two inventors sit in a different state from the assignee's HQ (Burleson, TX vs. Watertown, NY). That reflects NYAB's Texas engineering unit — NYAB today describes its Train Dynamic Systems (TDS) technology development unit in Irving, Texas (Knorr-Bremse NYAB release, 2024-09-03). It is a distributed-R&D fact, not an assignment-red-flag fact.
• The patent names "Hawthorne et al." and is cited by name in the forward-citation tables of US 7,656,834 and US 7,966,126.

---

Original assignee

New York Air Brake Corporation (recorded at filing; the entity is now styled New York Air Brake LLC).

Sources: https://www.nyab.com/en/ ; Knorr-Bremse news releases (2024-09-03; 2019-03-15); NYAB release 2018-06-12.

No bankruptcy, no wind-down, no portfolio liquidation is associated with NYAB at any point in the 2000–2026 window.

---

Assignment timeline

One entry. That is the entire recorded chain.

• 2001-04-24 (executed) / recorded 2001-05-03 — Reel 011776 / Frame 0666
  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNORS INTEREST)
  • Assignor: Hawthorne, Michael J.; Nickles, Stephen K.; Haley, John E. (all three, jointly)
  • Assignee: NEW YORK AIR BRAKE CORPORATION, New York
  • Correspondent: not exposed in any source I could retrieve. The recording data I obtained provides the reel/frame, the assignors, the assignee and the executed/recorded dates, but the cover-sheet correspondent field is not mirrored on Google Patents or Justia. Flagging as unresolved rather than guessing.
  • Context: Ordinary first-assignment / hire-to-employer conveyance, executed 2001-04-24 — nine days before the 2001-05-03 filing date of US 09/847,318 — capturing the CIP subject matter added over the parent US 09/624,049. No consideration-shifting, no security interest, no reorg.

No subsequent records in any category. The Google Patents legal-events table for this patent lists only: the 2001-05-03 assignment, the 2002-10-24 grant, then three maintenance-fee payments. There is no Change of Name, Merger, Security Agreement, License, Release, Correction, or second Assignment on this patent through the present date.

Consequences of that single-record chain:

• The corporation→LLC styling difference (Google Patents lists the "Current Assignee" as New York Air Brake LLC while the recorded assignee is New York Air Brake Corporation) is not backed by a recorded Change of Name or Merger in the data I retrieved. Either the conversion was handled at the parent-entity level without a per-patent recording, or it is a Google normalization artifact. Unresolved — flagged, not asserted.
• The patent's term ran out (anticipated expiration 2020-07-24) with the original family still in place. There was never a window in which the '766 was detached from NYAB.

---

Timeline diagram

timeline
    title Ownership of US 6480766
    2000 : Priority date Jul 24
         : Parent case 09624049 filed
    2001 : Inventors assign to NYAB Apr 24
         : Recorded May 3 reel 011776 frame 0666
         : Parent US 6311109 issues Oct 30
    2002 : US 6480766 issues Nov 12
    2006 : Year 4 maintenance fee paid
    2010 : Year 8 maintenance fee paid
    2014 : Year 12 maintenance fee paid
    2020 : Anticipated term expiration Jul 24

---

NPE / troll-pattern signals

Independent anti-NPE datapoints worth carrying forward:

• Maintenance fees were paid at the 4-year (2006-05-12), 8-year (2010-05-12) and 12-year (2014-05-12) anniversaries — a company that intended to abandon or flip the asset does not keep paying to year 12 and then stand on it to expiry.
• The named inventor became the assignee's CEO and later CEO of a sister subsidiary. That is an internal-succession story, the antithesis of the "all inventors gone within 12 months" precursor.

Caution on a false positive I want to pre-empt: my search for litigation around '"076 patent" surfaced a PTAB petition (ptacts.uspto.gov/ptacts/public-informations/petitions/1557691) referencing an "’076 patent" in a 2024 Eastern District of Texas / TSMC-UMC dispute with a June 2026 trial. That is a different patent in the semiconductor art being asserted against TSMC and UMC. It is not US 6,480,766. Do not cross-contaminate the two.

---

Verdict

Insufficient data (only the original assignment)

Applied literally to the rubric: the chain contains one record — reel 011776/0666, executed 2001-04-24 and recorded 2001-05-03 — and nothing else. There is no post-issuance assignment record to analyse, so the "2+ strong signals" and "1 strong or 2+ weak" thresholds for an NPE call cannot be met, and I will not manufacture signals from an empty record.

Substantively, though, the absence of records is the conclusion: this is a clean, never-transferred operating-company patent. All eight NPE signals are "not present" (with Signal 3 unresolved purely as a data-retrieval gap), the assignee New York Air Brake LLC is a live, product-shipping rail-braking manufacturer and Knorr-Bremse subsidiary whose own LEADER System is the commercial embodiment referenced in the specification, the inventors' lead never left the corporate family, and the patent was carried by fee payments at years 4, 8 and 12 to its 2020-07-24 term expiry. Had the rubric offered "operating-company ownership — no assertion indicated," that would be my call; on the available options, Insufficient data is the honest one, and the reason is the thinness of the record rather than any ambiguity about who owned the patent.

Verification links: https://assignment.uspto.gov/patent/index.html (search patent number 6,480,766 — this is where the correspondent-of-record for reel 011776/0666 can be read and where Signal 3 can be resolved) · https://assignmentcenter.uspto.gov/ · https://patents.google.com/patent/US6480766/en · https://patents.justia.com/patent/20020010531

I'll research the specific prior-art references cited on the face of US 6,480,766 to assess their § 102 relevance. Let me run targeted searches.

Let me gather details on the remaining rail-specific references cited on the face of '766.

Prior-Art Analysis for US 6,480,766 B2

Search scope note. I ran targeted searches for the literal strings "6480766" / "6,480,766" and for the individual reference patents cited on the face of US 6,480,766. As instructed, I did not substitute lookalike numbers. The reference set below is exactly the 20 U.S. patents listed under "Citations (20)" on the face of US 6,480,766 (per the authoritative Google Patents record at https://patents.google.com/patent/US6480766/en), plus the single non-patent citation. Cross-referenced detail came from the individual reference documents (Google Patents / patentimages PDFs / FreePatentsOnline / Justia).

I am building on — not repeating — the earlier sections. The earlier section established that the four issued claims are narrow: they are confined to determining which branch track a train is on after a switch, using a "before/at switch" position and an "after switch" position compared to an onboard database, with three dependent variants (simultaneous two-point, sequential single-point, and error carry-forward). That claim framing drives the § 102 analysis below.

---

Legal framework applied

• Priority / filing. Priority date 2000-07-24; filed 2001-05-03. Because the application predates the AIA's first-to-file date, pre-AIA 35 U.S.C. § 102 governs. All 20 cited references issued/filed before the priority date and therefore qualify as prior art (most expressly as § 102(a)/(b), and the later-issued ones under § 102(e)).
• Anticipation standard. § 102 anticipation requires a single reference disclosing every limitation of a claim, arranged as in the claim. Where a reference touches only some limitations, I say so and note the limitation(s) it lacks.
• Bottom line up front: On the face of the record, no single cited reference appears to anticipate claims 1–4. The citations are far more relevant as § 103 (obviousness) art — particularly as combinations against claim 1 — and as evidence of claim construction. I flag this candidly rather than force an anticipation theory.

---

Master reference table (all 20 examiner-cited U.S. patents)

Non-patent citation: Vehicle Positioning — Do you know where your train is?, Railway Age, Feb. 1996, pp. 41–42 (industry survey; general background, not anticipatory).

---

Detailed § 102 analysis — the references that matter

A. US 6,128,558 — Wabtec Railway Electronics (filed 1998-06-09; issued 2000-10-03) — highest relevance

Citation: U.S. Patent 6,128,558 B1, "Method and apparatus for using machine vision to detect relative locomotive position on parallel tracks," assigned to Wabtec Railway Electronics, Inc.; inventors Jeffrey D. Kernwein et al.
Description: Onboard system (FIG. 2) with GPS receiver 206, wheel tachometer 212, and an onboard computer 210 that "may include a comprehensive rail track database," plus a "turnout detector 222 … capable of detecting if the train has made a turn or switched tracks." The turnout detector uses a forward-looking image sensor and image/line-detection algorithms to resolve which of a group of parallel tracks the train occupies.
Why it matters for '766: This is the same problem the '766 claims target, and the '766 specification itself cites it ("Due to the limit of accuracy of GPS data, U.S. Pat. No. 6,128,558 suggests using machine vision to detect relative locomotive position on a parallel track"). Its background expressly canvasses and disparages GPS-only, DGPS, track-circuit, and inertial approaches for parallel-track disambiguation.
§ 102 verdict: Does not anticipate claims 1–4. It lacks the claimed core — determining a first position before/at a switch and a second position after the switch and comparing those determined positions to a database to pick the branch. Its disambiguation is machine-vision, not position-vs-database. It is, however, the single most important § 103 reference and a key claim-construction anchor (it frames the "which parallel track" problem and the known inadequacy of standalone GPS).

B. US 6,081,769 — Wabtec (filed 1998-02-23; issued 2000-06-27) — high relevance

Citation: U.S. Patent 6,081,769, "Method and apparatus for determining the overall length of a train," inventor Dwight D. Curtis, assigned to Wabtec.
Description: First GPS receiver on the end car and second GPS receiver on the lead locomotive determine geo-referenced end-of-train and front-of-train positions; a processor (front-of-train unit 204) computes train length. Critically, it discloses a database 226 storing geo-referenced track coordinates, against which the determined positions are compared, including a known coordinate position of a siding or switch — the processor warns the crew as the train approaches or clears a siding or switch.
§ 102 verdict: Does not anticipate claims 1–4. It gets close on the "compare a determined position to an onboard database of track points (including a switch)" element, but it does not determine which branch of a diverging switch the train took, and its second measurement is not a within-switch "after" reading used for branch selection. Strong § 103 art for the "compare determined positions to an onboard database" limitation of claim 1.

C. US 5,129,605 — Rockwell (filed 1990-09-17; issued 1992-07-14) — high relevance

Citation: U.S. Patent 5,129,605, "Rail vehicle positioning system," Rockwell International Corp. (Burns et al.).
Description: Train Control Computer (TCC) determines train position by interpreting GPS or transponder signals and dead-reckoner data and comparing them to a "track data base, which contains all the features of the expected route." The system expressly resolves ambiguities between information from the various sources, validates each source, corrects sources where possible, and prioritizes them. Claim 7 of '605 recites "means for providing switch position reports from track switches."
§ 102 verdict: Does not anticipate claims 1–4. It discloses comparing determined GPS positions to an onboard route/track database and using the database to resolve location ambiguity — the general mechanism of claim 1 — but it does not disclose the two-position (before/at and after switch) comparison to select a branch track. Strong § 103 art and background support for "comparing … to a data base."

D. US 5,867,122 — Harris (filed 1996-10-23; issued 1999-02-02) — high relevance

Citation: U.S. Patent 5,867,122, "Application of GPS to a railroad navigation system using two satellites and a stored database," Harris Corp.
Description: A vehicle constrained to a known route carries a route database; the database maps elapsed distance to an estimated 2D/3D location, and the estimate is corrected using as few as two GPS satellites via angle/range-error computation (Kalman-filter dead reckoning + GPS correction). Also discloses placing the unit at the rear of a train as well as the locomotive.
§ 102 verdict: Does not anticipate claims 1–4. It improves location accuracy of a single position estimate along a route using a stored database; there is no switch, no "before vs. after" two-position branch determination. Relevant as § 103 background on GPS-plus-database location correction.

E. US 5,574,649 — Levy (filed 1991-09-27; issued 1996-11-12) — relevant to claim 4

Citation: U.S. Patent 5,574,649, "Position-locating method and apparatus including corrections for elevational changes," Nessim I. Levy.
Description: GPS-based position locating with corrections applied to the satellite-derived position (including differential-style and elevation-change corrections).
§ 102 verdict: Does not anticipate claims 1–4. It addresses position error correction generally, which is conceptually adjacent to claim 4's "determine an error … and assume the same error for the second determined position," but it does not disclose that specific two-position, common-error-assumption step at a switch. § 103 material for claim 4 only.

F. US 5,590,856 — Quinn (filed 1994-10-28; issued 1997-01-07) — switch-specific

Citation: U.S. Patent 5,590,856, "Complex switch turn-out arrangements using proximity selection," Patrick A. Quinn.
Description: Addresses switch turn-out arrangements (complex trackwork at turnouts) using proximity selection — i.e., wayside/proximity sensing to distinguish turnout routes.
§ 102 verdict: Does not anticipate claims 1–4. Although squarely about switches/turnouts, the mechanism (proximity selection) is not the claimed before/after GPS-position-vs-database comparison. Relevant as § 103 art showing the switch-disambiguation objective was known. Caveat: I did not retrieve the full claim text of '856 in this session; the assessment rests on its title and known subject matter — verify against the document.

G. US 5,969,643 — Westinghouse Air Brake (filed 1998-02-23; issued 1999-10-19) — relevant to claim 2

Citation: U.S. Patent 5,964,643 / 5,969,643, "Method and apparatus for determining relative locomotive position in a train consist," WABCO; inventor Dwight D. Curtis.
Description: A GPS receiver mounted on each locomotive of a consist (lead 102 and trailing 104) communicates position to a controller/processor 112, which determines the relative positions of locomotives and tracks/verifies consist configuration as cars are added/removed.
§ 102 verdict: Does not anticipate claims 1–4. It anticipates the architectural premise of dependent claim 2 — GPS receivers at two spaced locations along the train, positions communicated to a processor — but not the switch/branch determination. § 103 material for claims 2 (two spaced GPS units) and the "position determining devices at two … spaced locations" underpinning.

H. US 6,218,961 — G.E. Harris (filed 1996-10-23; issued 2001-04-17) — moderate–high

Citation: U.S. Patent 6,218,961, "Method and system for proximity detection and location determination," G.E. Harris Railway Electronics, L.L.C. (same Oct. 23, 1996 priority family as US 5,867,122).
Description: Proximity detection and location determination for rail vehicles (GPS-aided, database-aided).
§ 102 verdict: Does not anticipate claims 1–4 on the switch/branch method; relevant as § 103 background on GPS-plus-database location determination. Qualifies as § 102(e) art (filed 1996, issued 2001). Caveat: full claim text not retrieved this session.

I. US 5,740,547 — Westinghouse Air Brake (filed 1996-02-20; issued 1998-04-14) — high relevance

Citation: U.S. Patent 5,740,547, "Rail navigation system," Westinghouse Air Brake Co. (Kull et al.).
Description: Rail navigation system using GPS/position inputs and an onboard track/database reference (a core "rail navigation" reference, expressly cited in the '766 specification as one of the prior systems for determining locomotive position via GPS and onboard databases).
§ 102 verdict: Does not anticipate claims 1–4. It is foundational background for GPS-plus-onboard-database rail navigation (supporting the "data base on the train" element), but does not disclose the two-position switch-branch determination. § 103 material. Caveat: assessment based on title and the '766 specification's characterization; full claim text not retrieved this session.

J. US 6,135,396 — GE-Harris (filed 1997-02-07; issued 2000-10-24) — moderate

Citation: U.S. Patent 6,135,396, "System and method for automatic train operation," GE-Harris Railway Electronics, LLC.
Description: Automatic train operation with GPS/position determination and movement-authority enforcement.
§ 102 verdict: Does not anticipate claims 1–4. Background on train-control positioning; no switch-branch position-vs-database method. § 103 background. Caveat: full claim text not retrieved this session.

K. US 6,246,956 — Toshiba (filed 1998-10-02; issued 2001-06-12) — moderate

Citation: U.S. Patent 6,246,956 B1, "Vehicle traffic control apparatus," Kabushiki Kaisha Toshiba.
Description: Vehicle traffic control apparatus (position-based control).
§ 102 verdict: Does not anticipate claims 1–4. Peripheral background; § 103 only. Caveat: full claim text not retrieved this session.

L. US 5,437,422 — Westinghouse Brake & Signal (filed 1992-02-11; issued 1995-08-01) — moderate

Citation: U.S. Patent 5,437,422, "Railway signalling system," Westinghouse Brake and Signal Holdings Ltd.
Description: Railway signalling with fixed-position references (e.g., transponders at points) used to identify vehicle position along the route.
§ 102 verdict: Does not anticipate claims 1–4. Relevant only as background that position determination at "points/switches" was known. Caveat: full claim text not retrieved this session.

---

Lower-relevance references (brief)

These are non-rail or general navigation references; all are cited, but none anticipates the switch/branch claims:

• US 4,638,438 (Hitachi, 1983/1987) — automotive navigation/map-matching. General "compare measured position to a stored map/database" concept; no rail, no switch. § 103 background at best.
• US 4,807,127 (Sumitomo, 1986/1989) — vehicle location detecting (dead-reckoning + map matching). Same posture as above.
• US 4,863,123 (SNCF, 1986/1989) — localizing a rail mobile unit (beacon/odometry). Rail context, but no GPS-vs-database switch-branch method.
• US 5,334,986 (Philips, 1992/1994) — vehicle position determination. General.
• US 5,374,933 (Zexel, 1993/1994) — position correction for vehicle navigation (map matching/error correction). Potential § 103 support for the "error" concept in claim 4 only.
• US 5,394,333 (Zexel USA, 1991/1995) — correcting GPS position in a hybrid navigation system. Same posture (claim 4 error-correction concept).
• US 5,791,063 (Ensco, 1996/1998) — automated track location identification from measured track data (track geometry, not vehicle GPS). Low relevance.
• US 5,809,448 (CAF, 1995/1998) — position detector for guide vehicles. Low–moderate.

---

Claim-by-claim § 102 summary

---

Analyst conclusions & caveats

1. No anticipation on the face of the record. Every claim of '766 requires a switch-branch determination from two position readings (before/at and after the switch) compared to an onboard database, and no cited reference discloses that complete sequence. The examiner cited these references as background and § 103 material; the issued claims are deliberately narrowed to the switch-branch method.

2. Rank-ordered most-relevant references for the '766 claims:

• US 6,128,558 — highest (same parallel-track problem; GPS + onboard rail DB + turnout detector; expressly cited in the '766 spec).
• US 5,129,605 and US 6,081,769 — next (position-vs-onboard-database, switch/siding references).
• US 5,867,122, US 5,740,547, US 5,969,643 — GPS + database / multi-receiver architectures (claims 1–2 support).
• US 5,574,649 (+ Zexel 5,394,333 / 5,374,933) — claim 4 error-correction concepts.
• US 5,590,856 — switch/turnout context.

1. Verification limitations (stated explicitly rather than fabricated):

• I confirmed titles, assignees, and priority/publication dates for all 20 references from the authoritative Google Patents citation table for US 6,480,766.
• I retrieved full text for US 5,969,643, US 6,128,558, US 6,081,769, US 5,867,122, and US 5,129,605, and assessed those directly.
• For US 5,590,856, US 5,740,547, US 6,218,961, US 6,135,396, US 6,246,956, US 5,437,422, US 5,791,063, US 5,800,448 and the older navigation patents, I reached the step limit before retrieving full claim text; those assessments rest on the titles and the '766 specification's own characterizations. They should be confirmed against the documents before being relied on in a validity opinion.

1. Cross-reference / consistency check with the prior sections: Consistent — the prior section identified these same references as "direct competitive antecedents" and stressed that the claims are narrower than the disclosure. Nothing here contradicts that; this section adds the per-reference § 102 mapping. If any authoritative source shows a cited reference teaching the full two-position switch-branch comparison to an onboard database, that would change the conclusion for claim 1 and should be surfaced.

Sources: https://patents.google.com/patent/US6480766/en (citation table, claims, spec); reference documents at patentimages.googleapis/patentimages.storage.googleapis.com (US 5,969,643; US 6,128,558; US 6,081,769; US 5,867,122; US 5,129,605); https://www.everypatent.com/comp/pat6128558.html and https://uspto.report/patent/grant/6081769 (descriptions).

I'll ground this § 103 analysis by verifying what the cited references actually disclose, starting with the most load-bearing ones for each claim element.

Obviousness Analysis — US 6,480,766 B2 under 35 U.S.C. § 103

Analysis date: April 26, 2026 (per this task's date field; note the earlier sections in this file were generated with a 2026-09-30 retrieval stamp — the discrepancy is immaterial here because the patent's term has already run).

Scope note. This section builds on the previously generated bibliographic, abstract, and claim-construction material and does not repeat it. It uses the prior-art record from the patent page (the 20 examiner‑cited references, the 4 "family cites," and the Railway Age non-patent citation at https://patents.google.com/patent/US6480766/en). Where I quote a reference, I verified the text against the source URL shown. Where a reference is characterized only from its title/assignee/field, I say so.

---

1. Framework and threshold issues

The controlling inquiry is Graham v. John Deere Co., 383 U.S. 1 (1966), as refined by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007). The question is not whether each element is found somewhere, but "what the combined teachings of the references would have suggested to those of ordinary skill in the art." In re Keller, 642 F.2d 413, 425 (CCPA 1981). Motivation may be implicit in the "nature of the problem to be solved." In re Merck & Co., 800 F.2d 1091, 1097 (Fed. Cir. 1986). Only a reasonable expectation of success is required, not certainty. In re O'Farrell, 853 F.2d 894, 903 (Fed. Cir. 1988).

Three threshold points drive everything below:

(a) All references are analogous art. Every cited reference is from the same field of endeavor — railway vehicle positioning/navigation — so the analogous-art gate is not contested.

(b) Reference timing. US 5,867,122 (1999), 5,740,547 (1998), 5,969,643 (1999), 5,129,605 (1992), 5,590,856 (1997), 6,081,769 (issued 2000-06-27), and the Railway Age article (Feb. 1996) all predate the 2000-07-24 priority date. US 6,218,961 (filed 1998-02-20; issued 2001-04-17), US 6,128,558 (filed 1998-06-09; issued 2000-10-03), US 6,138,596 (filed 1998-02-06; issued 2000-10-24) and US 6,246,956 (filed 1998-10-02; issued 2001-06-12) were published/issued after the priority date but have earlier effective filing dates, so each qualifies as § 102(e) prior art as of its filing date.

(c) The applicant's own specification supplies binding admissions. The '766 specification expressly concedes that "GPS and other devices have been used to determine the position of the train. Data bases are provided on the locomotive as a point of comparison," citing 5,129,605, 5,740,547 and 5,867,122 — i.e., it concedes the core of claim 1 (GPS positions compared to an on-board track database). It further admits that "[p]rior art systems have used the heading as an indication of which branch the train is on after passing through the switch," and that GPS error "does change at a significantly slow rate," so for short periods "the error can be considered effectively constant." These statements narrow the gap between the claims and the art and are usable against the patent. See Riverwood Int'l Corp. v. R.A. Jones & Co., 324 F.3d 1346, 1354–55 (Fed. Cir. 2003).

(d) The alleged point of novelty is largely not claimed. As noted in the earlier claim-construction section, the specification's touted advance is determining the branch "without the use of a heading." But no claim recites the absence of heading. Claim 1 is agnostic on heading. Claim 1 therefore cannot obtain patentability from the heading-free feature; its patentable weight rests only on the "first position before/at the switch → second position after the switch → compare both to an on-board database → determine branch" sequence.

---

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

A person of ordinary skill as of July 2000 would have held a bachelor's degree in electrical, mechanical, or computer engineering (or equivalent) plus roughly 2–5 years of experience in railway location/navigation systems, or a master's degree with less experience. That person would be familiar with: GPS/DGPS error characteristics (including slowly varying bias), dead reckoning with wheel tachometers and gyros, Kalman filtering, on-board track databases, and the long-recognized problem of resolving which of two closely spaced parallel tracks or switch branches a train occupies. This is consistent with the level reflected in the references themselves.

---

3. The prior-art landscape as verified

Characterized from title/field only (not full-text verified): US 5,394,333 ("Correcting GPS position in a hybrid navigation system," Zexel), US 5,374,933 ("Position correction method for vehicle navigation system," Zexel), US 5,574,649 (Levy, position-locating with elevation corrections), US 5,334,986 (Philips), US 4,863,123 (SNCF railroad localization), US 4,638,438 / 4,807,127 (automotive navigation), US 5,437,422 (Westinghouse railway signalling), US 6,081,769 (Wabtec train length), US 6,128,558 (Wabtec machine-vision parallel-track detection), US 6,138,596 (GE-Harris automatic train operation), US 6,246,956 (Toshiba vehicle traffic control). I flag these as title/field-level only because my retrieval budget was exhausted before full-text confirmation.

---

4. Claim charts and proposed grounds of rejection

Claim 1 — independent

Claim 1: (i) determine a first position of a train portion before/at a switch; (ii) determine a second position after the switch; (iii) compare the first and second positions to an on-board database; (iv) determine which branch track from that comparison.

Primary Ground: 5,740,547 in view of 6,218,961. 5,740,547 supplies the whole architecture — on-board computer + track database with switches, GPS/odometer/heading inputs, and generation of a track identifier after passing a switch. 6,218,961 supplies the database-driven candidate-path resolution within the GPS uncertainty region and the explicit "declare the surviving path" step. Both are the same field, address the same problem (parallel-track/switch disambiguation), and the examiner already cited both. One of ordinary skill would combine them because 6,218,961 is literally a CIP of 5,867,122 in the same Harris/GE-Harris line and its claim 11 is designed to solve precisely the deficiency 5,740,547 identifies ("not accurate enough to determine on which of two adjacent parallel tracks").

Alternative Ground: 5,740,547 in view of 5,129,605. 5,129,605 adds the successive-fix mapping and bracketing-segment/error-threshold logic that supplies the "first position … second position … compare to the database" sequence.

Why obvious: (a) both references are directed to the same problem and are combinable by simple substitution of one database-driven localization routine for another; (b) the '766 specification concedes the GPS+database architecture as prior art; (c) the only feature arguably distinguishing the claim from 5,740,547 is the use of two database comparisons rather than a heading-based switch detection — but (i) claim 1 does not exclude heading, so 5,740,547's heading-augmented switch detection also reads on it, and (ii) taking two position readings straddling a known divergence point is the most predictable manner of doing what 5,740,547 already does continuously.

KSR rationales (MPEP § 2143): (1) combining prior art elements (GPS position fixing; on-board track database; database lookup around a switch) according to known methods to yield predictable results; (2) simple substitution of a known database-comparison technique for a known heading technique; (3) use of a known technique (uncertainty-region path elimination) to improve a similar device in the same way; (4) the problem was known and the solution was obvious to try, in a field with a finite number of identified, predictable solutions.

Claim 2 — simultaneous two spaced portions

Adds: the first and second positions are determined simultaneously at two spaced portions of the train.

Ground: Claim-1 combination + US 5,969,643. 5,969,643 is dispositive: "A receiver is mounted to each of the locomotives of a train consist … A communication device, such as a radio frequency (RF) transmitter or transceiver … A processor … determines a relative position." That is the exact FIG. 4A mode (head-end and rear-end receivers, simultaneous fix, RF intercommunication). 5,867,122 independently discloses the same two-ended architecture ("installing the system at the rear of a train in addition to, or instead of, the train locomotive"). Motivation: 5,969,643 and 5,867,122 were both addressing consist configuration/position verification, and a POSITA would recognize that a second, spaced receiver provides a second independent database comparison with negligible added complexity.

Claim 3 — sequential single point

Adds: the first and second positions are determined sequentially at the same portion of the train.

Ground: Claim-1 combination + US 5,867,122 and/or US 5,129,605. Both disclose periodic, sequential position fixes by a single receiver as a vehicle advances — 5,129,605's "at periodic intervals … send a time tagged distance value corresponding to GPS derived position … as a correction to its next dead reckoned data block report," and 5,867,122's periodic reads of the dead-reckoning estimate. Taking a reading before the switch and a second reading after it is the same operation with the switch as the reference point. The specification's own admission that GPS error is "effectively constant" over short periods supplies the enabling rationale for why sequential readings suffice — a rationale a POSITA would derive from the references' FOM/error-threshold teachings in 5,129,605.

Claim 4 — error carry-forward

Adds: determining an error between the first determined position and the database, and assuming the same error for the second determined position.

Ground: Claim-1 combination + US 5,129,605 (and/or the Zexel references 5,374,933 / 5,394,333). 5,129,605 expressly computes a "cross-track error … less than some maximum which depends on figure of merit (FOM)" between the GPS-reported position and the database track segment, and expressly applies that correction to the next position report ("uses this input as a correction to its next dead reckoned data block report and flags it as corrected"). "Correcting GPS position in a hybrid navigation system" (US 5,394,333) and "Position correction method for vehicle navigation system" (US 5,374,933) are, from their titles and field, directly on point for estimating a position error and applying it to a subsequent measurement. The '766 specification itself supplies the scientific predicate — "the error … does change at a significantly slow rate. Thus, for a relatively small time periods, the error can be considered effectively constant."

Motivation to combine is strong and articulated: carrying forward a slowly varying GPS bias measured against a known, high-accuracy track database is the standard differential/GPS-augmentation technique of the era, and 5,129,605 already does the "measure error against the database, then correct the next fix" operation.

---

5. Consolidated motivation-to-combine and reasonable expectation of success

Motivation. All references are in the same field, target the same recognized deficiency (GPS accuracy insufficient to distinguish closely spaced parallel/switch tracks), and come from the same small set of rail suppliers (Westinghouse Air Brake, Harris/GE-Harris, Rockwell, Wabtec). The '766 applicant itself cited the same references as the state of the art. When multiple independent actors converge on the same problem with the same toolkit, the motivation requirement of KSR is easily satisfied, and the motivation may be "implicit in the nature of the problem." In re Merck, 800 F.2d at 1097.

Reasonable expectation of success. The references demonstrate each ingredient working: database-constrained GPS localization (5,867,122; 5,129,605), tracking switch events against an on-board database (5,740,547), candidate-path elimination within an uncertainty region (6,218,961), and two-receiver consist positioning (5,969,643). The combination is a predictable assembly of known elements, so the results would be predictable. Wm. Wrigley Jr. Co. v. Cadbury Adams USA LLC, 683 F.3d 1356, 1364 (Fed. Cir. 2012).

---

6. Anticipated counterarguments and responses

1. "The references teach away — they use heading or machine vision, not two-position GPS/database comparison." 5,740,547 and 6,218,961 use heading; 6,128,558 uses machine vision. But a reference teaches away only if it "criticizes, discredits, or otherwise discourages" the claimed approach. Mere disclosure of an alternative does not. In re Ratti, 270 F.2d 810, 813 (CCPA 1959); In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994). None of these references disparages a database-driven, two-reading comparison; indeed 5,740,547's own objective is to "determine which of a set of parallel and adjacent tracks the train consist is moving on," which is the '766 problem. Under KSR, the fact that a course of action has competing alternatives does not negate motivation to combine.

2. "GPS error makes the second reading unreliable." That is exactly the problem claim 4 solves, and the references teach the solution (5,129,605's FOM-based error; Zexel's correction). And the '766 specification itself concedes the error is slowly varying, so a POSITA would assume it constant over the short switch-crossing interval — a design choice the claims merely memorialize.

3. "Secondary considerations compel non-obviousness." No evidence of unexpected results, commercial success, licensing, or industry praise with nexus is in this record. Absent such evidence, the Graham secondary factors do not rebut the strong prima facie case. (The patent expired 2020 and shows no litigation or IPR activity that produced such evidence.)

4. "The examiner allowed the claims, so they must be non-obvious." Allowance is not an adjudication of validity. The record above shows: (a) the claim-1 architecture was conceded prior art; (b) the touted heading-free feature is unclaimed; and (c) the differentiators (two-reading comparison; simultaneous/sequential modes; error carry-forward) were each separately disclosed. That is the classic posture for a § 103 rejection notwithstanding allowance.

---

7. Bottom line

• Claim 1: apparent § 103 rejection over US 5,740,547 in view of US 6,218,961 (alternative: further in view of US 5,129,605). Every element is disclosed or rendered obvious; motivation is supplied by the common problem and the applicant's own admissions.
• Claim 2: apparent § 103 rejection over the claim-1 combination in view of US 5,969,643 (and/or 5,867,122).
• Claim 3: apparent § 103 rejection over the claim-1 combination in view of US 5,867,122 and/or US 5,129,605.
• Claim 4: apparent § 103 rejection over the claim-1 combination in view of US 5,129,605 (and/or US 5,374,933 / US 5,394,333).

Caveats I want to keep visible. (1) Full-text review was completed for 5,867,122, 5,740,547, 5,969,643, 6,218,961, 5,129,605 and (partially) 5,590,856; the remaining references are characterized at the title/field level only, so any rejection that turns on those should be re-verified against the printed documents before being relied upon. (2) I did not locate any grant, IPR, or Federal Circuit record addressing the validity of this patent — the earlier CAFC 2026 docket check stands, and no adjudicated obviousness holding (either way) has been located, so this analysis reflects the "as-issued" claims, not narrowed claim constructions from any post-grant proceeding.

Non-prior-art aside (not relied upon): The document I retrieved at CA 2518192 C1 (https://patentimages.storage.googleapis.com/d6/36/8e/f66d351081cf72/CA2518192C.pdf) pursues a very similar concept — computing an error vector against the correct path before a divergence, then a second vector after divergence, and comparing the vectors to pick the branch. It carries a 2004 priority date and is therefore not prior art to the '766 claims; I flag it only because it corroborates that the '766 claim-1/claim-4 concept was, a few years later, treated as a conventional differential-GPS technique by a different assignee (Quantum Engineering / Ford). This cuts toward predictability but should not be cited as prior art against the '766 patent.