Hydrogen locomotives offer a promising cleaner alternative to conventional diesel locomotives. However, hydrogen production methods and energy sources may introduce additional emissions. This paper evaluates the environmental and potential social impacts of hydrogen locomotives in Canada from a life cycle perspective, encompassing the locomotive's retrofitting components and the fuel life cycle. Results show varying emissions across different hydrogen production pathways and regions. Electrolysis has the highest emission reduction potential in provinces with cleaner electricity sources, such as Manitoba, Quebec and British Columbia, resulting in up to 47% reduction in life cycle emissions. Conversely, in Alberta and Saskatchewan, emissions are approximately three times higher than diesel due to reliance on fossil fuel-derived electricity. The social assessment underscores the imperative of considering emissions, costs, and technical implications to address potential social impacts. This positions hydrogen locomotives with significant challenges that necessitate resolution before they can be considered a superior alternative to diesel.