As enterprises, data and functions become increasingly complex and distributed the need for information systems to be both customisable and interoperable also increases. Large scale engineering and scientific projects demand flexibility in order to evolve over time and to interact with external systems (both newly designed and legacy in nature) while retaining a degree of conceptual simplicity. The design of such systems is heavily dependent on the flexibility and accessibility of the data model describing the enterprise's repository. The model must provide interoperability and reusability so that a range of applications can access the enterprise data. Making the repository self-describing, based on 'meta-object' structures, ensures that knowledge about the repository structure is available for applications to interrogate and to navigate around for the extraction of application-specific data. In this paper, a large application is described which uses a meta-object based repository to capture engineering data in a large data warehouse. It shows that adopting a meta-modeling approach to repository design provides support for interoperability and a sufficiently flexible environment in which system evolution and reusability can be handled.