Hydrogen trains cannot be considered a success in decarbonization merely by their introduction; the key question is whether they can replace diesel trains and reduce both emissions and costs across the entire lifecycle—from fuel production to operation. Commercial operation of hydrogen trains is scheduled to begin in 2027 on the Brescia–Iseo–Edolo line in Lombardy, targeting non-electrified routes as a replacement for diesel trains. There is not just one method of hydrogen production. In Edolo, hydrogen will be produced via electrolysis of water using renewable electricity, while in Iseo, production will involve biomethane with carbon capture. Simply sharing the use of hydrogen does not mean their environmental performance can be equated. The total project scale is approximately €362.4 million (about ¥65.23 billion). Following infrastructure development, the next phase will demonstrate operational metrics such as utilization rates, fuel costs, and emission reduction effectiveness. The next challenge is proving, through concrete data, that the 2027 launch delivers returns commensurate with the investment.