An extensive optimum selection and design for closed-cell aluminum foam used in railway vehicle was performed based on the comprehensive energy absorption curves. These curves were obtained from kinds of foams with different density ratios loading at different strain-rates. Afterwards, an effective optimum selection as well as design was conducted. A reverse design process and optimum selection methodology was put forward by assuming the train collision scenario, determining the overall energy-absorbing requirement, constructing the mapping relationship between standardized stress and standardized energy absorption per unit volume, proceeding positive-going calculation of the energy-absorbing capacity at corresponding situation, and comparing, iterating circularly, until it converged to the optimal density ratio and optimal thickness. Finally, an optimization design example was given with crashworthy EMU head vehicle’s energy-absorbing component, and corresponding optimal density and thickness was obtained. This methodology turned out to be an effective and useful tool to aid in selecting the most appropriate aluminum foam.