Assessing hydrogen as an alternative fuel for rail transport - a case study

Diesel trains play a vital role in the UK's rail passenger transport. Despite efforts to expand electrification, over 10% of the UK's rail routes will remain non-electrified. To reduce emissions and phase out diesel trains by 2040, the UK rail network is actively exploring alternative fuels. This paper presents a comprehensive technical, economic, and environmental analysis of converting diesel trains to hydrogen-powered trains using a hydrogen combustion engine for the first time. A simulation-based methodology has been developed to assess train performance, fuel consumption, and emissions for both hydrogen and diesel engines. The developed methodology has been validated by comparing the predictions against the available experimental data and a very good agreement has been obtained. A case study involving British Class 195 diesel-powered regional trains on the Manchester Airport to Barrow-in-Furness route is analysed. The simulation results show that hydrogen-powered trains achieve zero carbon emissions and exhibit similar NOx emissions to diesel, with a similar performance. Over the train's 30-year lifespan, green hydrogen can reduce CO₂-equivalent emissions by up to 187.4 kt. The study clearly demonstrates that hydrogen combustion engines offer a practical, mid-term solution for decarbonizing regional rail, with much lower conversion costs compared with fuel cell technology.