This paper proposed the EGBOM, Extended Generic BOM, which is more flexible BOM system than GBOM. The GBOM system has the limitation to construct Result BOM and to select options by choosing only one Variant under given Cluster. In order to overcome this limitation, we propose the EGBOM which can make more various Result EGBOM, which can use to rolling stock through constructing urban transit BOM using the proposed EGBOM. The last, this paper describes the various Result BOM examples constructed from Source BOM of UT_EGBOM, such as rolling-stock maintenance BOM, individual car BOM, etc.