Maintenance operations directly influence the performances of railway vehicles and play a crucial role in railway services to provide uninterrupted and high quality service to passengers. With the exception of preventive activities, the demand of spare parts for maintenance tasks is usually random; hence, the fast and secure management of the spare parts inventory is an important factor for the successful execution of the maintenance process. The purpose of this research is to extend the classical ABC analysis by developing a multi-criteria inventory classifi- cation approach for supporting the planning and designing of a maintenance system. Relevant classifi- cation criteria and control characteristics of maintenance spare parts are identified and selected and discussed in terms of their effects on maintenance operations, purchasing characteristics, positioning of materials, responsibility of control, and control principles.