Hydrogen-powered passenger trains now cover an entire regional rail network in Lower Saxony, Germany — 14 Alstom Coradia iLint trains that have fully retired the diesel locomotives once used on the Cuxhaven-to-Buxtehude lines. Each train pulls oxygen from the air, combines it with hydrogen stored on the roof, and emits only water vapor, traveling roughly 1,000 kilometers between refuels. The regional operator has pledged to never buy another diesel train, citing both climate goals and the cleaner air passengers breathe at small-town platforms. It’s a modest fleet in a single corner of Germany, but it’s the first proof anywhere that diesel regional rail can be fully replaced — a template other countries with long, lightly used routes can now follow.