Determining the exact relationships between each component that comprises a digital twin is necessary for its definition. This study is focused on fully maintenance activities within a specialized railway maintenance provider. Exploring ontologies reveals relationships that are required to be determined, connecting the entities with essential data sources to build the digital twin of workshop maintenance management process. Objectives include ensuring traceability of records and timely data interpretation. This facilitates defining optimization levels and automation in decision-making, predicting risk levels during each review. Results reveal that the digital twin definition process starts by determining relationships among subsets of elements or entities in the maintenance process in a determinate domain and with the specific semantic. The research's potential extends to all rolling stock elements, emphasizing the current focus on specific mandatory inspections.