The most important part of RIMS(Rolling Stock Information Maintenance System) project is to construct BOM(Bill of Material). BOM is a listing or description of raw materials, parts, and assemblies that define a product. To construct BOM for RIMS is not a easy task due to several reasons such as data base scale and flexibility, proper integration between physical BOM and functional BOM, interoperability with other systems, etc. In this study we show several principles that Seoul Metro takes to get over the difficulties mentioned above. Based on these principles we propose the methodology Seoul Metro employs to construct BOM efficiently. We also discuss the applicability of BOM in several fields.