Hydrogen Fuel-Cell (HFC) technology is popular in Asia (mainly Japan), the US (chiefly California) and Europe. HFC is mostly used in passenger cars and urban buses. HFC technology is also being introduced to railway transport. Hydrogen-powered trains are an attractive alternative to diesel trains, in particular on nonelectrified railways - where roughly 70% of the world’s 200 000 locomotives operate today - and in the markets of Europe and the US (together about 55 000 diesel locomotives today). Besides avoiding carbon emissions, hydrogen trains reduce noise and eliminate local emissions of NOX and particulates. Since they use significant amounts of hydrogen, the required infrastructure is limited and can be immediately utilised. Hydrogen-powered trains are already being introduced for light-rail vehicles and regional railways - such as the trams produced by the China South Rail Corporation. Other models, including regional trains by Alstom, are expected to be deployed in the coming years. By 2030, one in ten trains sold for currently nonelectrified railways could be powered by hydrogen, by 2050, one in five trains running on nonelectrified railways or one in ten trains overall could run on fuel cells. Presently, two Coradia Lint trains are operated in Germany. In Poland by the end of 2018, 19 235 km of railways were used, of which 7 341 km (38%) were nonelectrified lines, mostly single-track (63%). Commodity transport was performed with 1470 electrical locomotives, 2070 diesel locomotives and 170 other rail transport vehicles. The objective of the article is to analyse the rationality of introducing HFC technology in Poland e.g. in terms of reduced CO2 emissions, based on current French, Romania, Spanish and Dutch experiences in multiple units and Latvian, German and Polish in shunters or Estonian, German and Swedish in mainline locomotives. The case study presented in this article focuses primarily on reducing CO2 emissions from Multiple Units.