Crashworthiness, strength and vibrational features of a railroad passenger car, which is originally made of steel members and then converted to an aluminium design, are studied. The finite element (FE) method is utilised for the static analysis in compliance with various scenarios defined in UIC CODE OR 577, modal analysis and simulation of the crash into a rigid wall. Firstly, a full-length, detailed passenger car model made of steel is used in FE analyses and the model is verified for the steel car body by comparisons with strain measurements and experimental evaluation of natural frequencies. The agreement between test measurements and FE results indicates that the FE model of the railroad car accurately represents the original structure. Following, effects of material change on the structural behaviour can be accurately judged based on the outcomes of the analyses. It is observed that the stress values and natural frequencies of the aluminium structure are almost equal to those of the original steel structure. Moreover, the crash energy absorption characteristics are within the acceptable tolerances for both cases. The final aluminium design is found to be about one-third of the weight of the initial steel structure while it preserves stiffness values within acceptable limits. In addition, an equivalent spring-mass system is developed to model the crash of both steel and aluminium passenger cars, which can be used for occupant safety investigations in future.