We are looking for a Senior Business / Functional Analyst for a long-term mission within a critical IT environment supporting railway traffic management systems. The role focuses on data consolidation, real-time processing, and distribution to internal and external stakeholders, ensuring reliable and efficient operations of key railway systems. Responsibilities Analyze business and functional needs across multiple stakeholders Translate requirements into clear functional and technical specifications Define and manage user stories within Agile/Scrum environments Optimize existing processes to improve performance and accuracy Collaborate closely with development teams to ensure alignment Design test cases and execute validation scenarios Perform impact analysis linked to business requirements Contribute to both new developments and maintenance of existing systems Scope Real-time and batch data processing (pre, post, back-office) Integration with external partners and European railway platforms Internal systems: scheduling, billing, energy consumption, data platforms API-driven ecosystems and data exchange services Profile / Requirements : Experience 10 years in business/functional analysis within IT projects Strong experience in Agile/Scrum methodologies Proven ability to gather and formalize business requirements Experience writing detailed functional documentation Solid background in user stories and backlog management Technical Expertise Modeling: UML, BPMN API & Web Services: REST, SOAP API tools: Postman, Swagger (or equivalent) Web security: JWT, OAuth Testing: test cases, test scenarios Data formats: XML, XSD, XPath Development knowledge: Java, .NET, or Python Languages French or Dutch: C2 level Second national language: B2 English: C1 Nice to Have Experience in railway or transport sector Experience in impact analysis and technical documentation Soft Skills Strong communication and stakeholder management Analytical mindset and structured approach Autonomous and proactive Team integration and collaboration Professional attitude and reliability