Electric and hydrogen rail: Potential contribution to net zero in the UK

•Improvements to train technology cannot solely be relied upon to reduce emissions.•Decarbonisation of the electricity generation mix is needed to reduce emissions.•Electric trains produce lower levels of cumulative emissions than hydrogen trains.•Conventional train emissions were 2.6 times lower than conventionally fuelled cars.•By 2050 conventional trains produce 5–14 times more emissions of new technology. Electric trains (ET) and hydrogen trains (HT) are considered zero emission at the point of use. True emissions are dependent upon non-tailpipe sources, primarily in energy production. We present UK carbon dioxide (CO2) operating emission model outputs for conventionally fuelled trains (CFT), ETs and HTs between 2017 and 2050 under four National Grid electricity generation scenarios. Comparing four service categories (urban, regional, intercity and high speed) to private conventionally fuelled vehicles (CFV) and electric vehicles considering average distance travelled per trip under different passenger capacity levels (125%, 100%, 75%, 50% and 25%). Results indicate by 2050 at 100% capacity CFTs produce a fifth of the emissions of CFVs per kilometre per person. Under two degree generation scenario, by 2050 ETs produced 14 times and HTs produced five times less emissions than CFTs. Policymakers should encourage shifts away from private vehicles to public transport powered by low carbon electricity.