Figure 4
On the far left, a vertical column labeled “Requirements” lists ten stacked boxes containing: “System”, “Stakeholder”, “Economical”, “Governance”, “Regulatory”, “Sustainability”, “Societal”, “Lifecycle”, “R A M S”, and “Technological”. To the right, the main process flow is shown horizontally. An arrow labeled “frame” from “Requirements” leads to a box labeled “Maintenance policy”. “Maintenance policy” connects downward to two subordinate boxes labeled “Maintenance” and “Maintenance support”. The “Maintenance policy” box outputs to the right with an arrow labeled “defines”, leading to a box labeled “Maintenance Concept”. “Maintenance Concept” connects upward to two subordinate boxes labeled “Indenture levels” and “Maintenance echeleons”. The “Maintenance Concept” box connects via an arrow labeled “implements” to a “Maintenance Process” box. Below the “Maintenance Process” box is a cluster of six smaller connected boxes forming the internal components of the process: Top row (left to right): “Maintenance management”, leading to “Maintenance support planning”, which leads to “Maintenance preparation”. Bottom row (left to right): “Maintenance improvement”, “Maintenance assessment”, and “Maintenance execution”. “Maintenance execution” leads to “Maintenance assessment”, which leads to “Maintenance improvement”. “Maintenance improvement” leads to “Maintenance support planning”. An arrow from the flow between “Maintenance improvement” and “Maintenance assessment” leads upward to “Maintenance preparation”. From the “Maintenance Process” box, an arrow labeled “guides” leads to “Maintenance policy assessment”. Above “Maintenance policy assessment”, a line leads to a group containing two subordinate boxes labeled “Requirement mapping” and “F M E C A”. The “Maintenance policy assessment” box sends an arrow labeled “informs” to the final box, “Maintenance policy improvement”. On the far right, beneath “Maintenance policy improvement”, six boxes are grouped to show advanced functions: “Condition monitoring”, “R U L estimation”, “Parameter Optimisation”, “Data Integration”, “Analytics”, and “Visualisation”. Dashed arrows from “Requirements” flow to the right to each box, representing “adaptation”. From each box on the right, dashed arrows loop back to “Requirements”, representing “interaction”.An approach for dynamic maintenance policy development for railway rolling stock