The Autonomous Train Operation System (TACS) is the development direction of future urban rail transit signal systems and is partly being applied in some urban rail transit. Different from traditional CommunicationsBased Train Control (CBTC), no unified TACS standard has been established yet. This paper aims to analyze the engineering applicability of existing TACS system degradation schemes. Based on the working principle of TACS, this paper discusses the necessity of configuring a degraded system. Drawing from the current development status of the TACS system, this paper summarizes three feasible TACS degradation schemes, introduces the architectures and working principles of different degradation schemes, and qualitatively analyzes the three TACS degradation schemes from the aspects of system composition, application scenarios, and tracking ability under degradation situation. The study establishes the train tracking time model under degradation situation, and simulates the degradation train tracking scenarios of three TACS degradation schemes under the same engineering conditions. Based on the simulation results, it identifies the factors that affect the efficiency of degradation tracking. Building on the above research, the key conditions for the TACS degradation system are summarized, and the engineering applicability and application effects of the three degradation schemes are analyzed, leading to several improvement suggestions. The results of this study have significant implications for the promotion and application of Train Autonomous Operation System.

urban rail transit  /  TACS  /  degradation system  /  trackside train management  /  autonomous perception  /  tracking ability