The article highlights the revival of an 80-year-old engine originally designed during World War II by US engineer Anselm Franz to run on hydrogen fuel. This opposed-piston engine design brought significant innovations by offering greater power density with less fuel consumption, making it suitable for aircraft propulsion. Modern-day advancements by Achates Power in California have optimized Franz's design, resulting in engines with 30% improved fuel efficiency compared to current diesel models. The simple mechanical structure of these engines ensures reliability and cost-effectiveness. The Hydrogen Opposed-Piston Engine Working Group, composed of various organizations, aims to further develop hydrogen combustion technology for opposed-piston engines. This collaborative effort envisions enhanced thermal efficiency and applications in sustainable transportation systems for long-distance travel and commercial fleets. Automakers like Toyota and BMW are actively exploring hydrogen combustion engines to replace internal combustion engines, with support from auto parts suppliers like Bosch. The article emphasizes the potential of hydrogen engines for mainstream automotive production but highlights the need for an expansive refueling system to facilitate their mass adoption in modern transportation. The historical development and modern innovations surrounding the hydrogen-powered opposed-piston engine serve as a bridge between past and future sustainable transportation systems, influencing the automotive industry's exploration of hydrogen as a viable transportation fuel.