Extreme floods occur in large territories and may cause significant damages to the railway system. As they are relatively rare, historical information about extreme floods is often not well known and used, whereas it could provide insights about: areas where the infrastructure is the most vulnerable, the resilience of the components of the railway system, and the financial and social impacts of extreme events. This paper deals with a framework to study historical extreme floods that can be used to model the flood processes impacting the railway system: IDISFER ontology. Ontologies are a flexible and interoperable data storage format, that is computer-readable and which can effectively process data. IDISFER includes all the relationships identified in the literature between natural flood phenomena and incidents on the railway system, causality relationships between several successive incidents (known as the 'domino effect') and chronological relationships between actions on the infrastructure and operations that are necessary to return the system to normal.