The paper proposes a scientific approach to solving the problem of forming the knowledge base and effective support system for decision-making by operational railway employees in the allocation of rolling stock depending on its merchantability. Analysis of existing regulations has shown the lack of a clear and unambiguous definition of merchantability of the rolling stock in regulatory documents, so contentious issues arise between the carrier and the shipper, especially in the reallocation of the rolling stock for loading. In this regard, almost complete lack of the formalized selection technology of rolling stock for loading was revealed. The results of solving the problem of merchantability assessment of the rolling stock allow to improve the quality of management decisions, primarily through the optimal use of internal resources, and the proposed solution methods based on fuzzy DSS can be used in conjunction with other control methods. It is important that the presented approach allows a more thorough merchantability assessment of the rolling stock by reducing the uncertainty of this matter in both regulatory, and technological terms. This issue is an integral part of the range of problems that arise when forming the system of logistics centers of Ukrainian railways.