Abstract: Objective When the onboard controller in TACS（train autonomous circumnavigation system） fails, the trackside resource request and release cannot be carried out successfully. Regarding this, it is necessary to propose a method for active resource request and release based on the backup localization system（hereinafter shorten as BLS）. Method An interface between the BLS and the onboard controller is added, enabling the BLS to inherit original tasks and control trackside resources when the primary onboard controller fails. The switchover mechanism between the primary on-board controller and the BLS is emphasized, as well as the technical implementation of resource request and release, and train interval protection by the BLS. The overall design of the BLS and the interface design between the BLS and onboard controller are elaborated. Result ＆ Conclusion The proposed method effectively simplifies the system architecture, reduces the impact of trackside train manager failures, while maintaining the existing train-to-train direct communication mode in TACS.