Metrom Rail v. Siemens Mobility — Federal Circuit Reverses PTAB, Finds All Railroad Collision-Avoidance Patent Claims Unpatentable

Background

Siemens Mobility, Hitachi Rail, Humatics Corp., and Piper Networks jointly petitioned for inter partes review of two Metrom Rail patents — U.S. Patent Nos. 9,043,131 and 8,812,227 — which relate to collision-avoidance systems for railroads. The patented systems use ultra-wideband (UWB) sensor technology and time-of-flight techniques to detect the separation distance between trains, providing operators with real-time proximity alerts.

The Patent Trial and Appeal Board found that all claims of the ‘227 patent and claims 1–16 of the ‘131 patent were unpatentable as obvious over the prior art, primarily a reference called Grisham. However, the Board determined that claims 17–20 of the ‘131 patent were not unpatentable, finding that the prior art did not disclose one key limitation: a wireless antenna “operable to send and receive data representing the separation distance over the air.” Metrom appealed the unpatentability findings; petitioners cross-appealed on claims 17–20.

The Court’s Holding

The majority, written by Judge Dyk, affirmed the Board’s unpatentability determinations for all claims challenged by Metrom (claims 1–16 of the ‘131 patent and all ‘227 patent claims). The court found that Metrom had forfeited key obviousness arguments by raising them only in its sur-reply, and that the Board’s findings of no nexus between Metrom’s commercial products and the claimed inventions were supported by substantial evidence.

On the cross-appeal, the majority reversed the Board’s finding that claims 17–20 were not unpatentable. The critical issue was the meaning of “data representing the separation distance” in claim limitation 17C. The Board had construed this phrase to mean only the computed separation distance — the final number. The majority disagreed, holding that in the context of the full claim — which explicitly requires time-of-flight techniques (17B) and communication between vehicle modules to detect separation distance (17G) — “data representing the separation distance” encompasses the pulse signals used in the time-of-flight calculation, not just the computed result. Since Grisham undisputedly discloses transmitting such time-of-flight pulse data over the air, the limitation was met.

Judge Taranto dissented on the cross-appeal, arguing that the petitioners never raised this claim-construction argument — either before the Board or on appeal — and that the majority was effectively resolving the issue on a theory that had been doubly forfeited. Judge Taranto would have affirmed the Board’s ruling that claims 17–20 are not unpatentable.

Key Takeaways

• In IPR proceedings, patent owners who raise new arguments only in sur-replies risk forfeiture — the Board has discretion to disregard late-filed theories.
• Claim construction remains outcome-determinative in IPR appeals: the difference between “computed distance data” and “data used to compute distance” was the entire basis for the reversal on claims 17–20.
• The dissent highlights a tension in Federal Circuit practice: should the court adopt a claim construction theory that neither party actually argued? The split suggests this issue may attract further attention in future cases.
• Secondary considerations of nonobviousness (commercial success, industry praise) require a clear nexus to the claimed invention — not just to the commercial product as a whole.

Why It Matters

This decision wipes out Metrom Rail’s entire patent portfolio covering railroad collision-avoidance technology, clearing the way for competitors including Siemens, Hitachi, and others to deploy UWB-based proximity detection systems without patent risk from these particular patents. The split between the majority and dissent on whether the court can resolve an issue on an un-argued claim-construction theory raises important questions about the scope of appellate review in IPR cases — a tension that practitioners should watch closely.