First hydrogen locomotive started working in Poland.
https://www.mobility.siemens.com/global/en/portfolio/rail/rolling-stock/commuter-and-regional-trains/alternative-drives.html
It's definitely a thing already.
This is a most excellent place for technology news and articles.
https://www.mobility.siemens.com/global/en/portfolio/rail/rolling-stock/commuter-and-regional-trains/alternative-drives.html
It's definitely a thing already.