A Comparative Headway Analysis of Hybrid Level 3 with TTD-Backup and Hybrid Level 3 (VSSs) in ETCS-Level 3 for Vietnam’s high-speed rail

Research on signaling technology for the feasibility study and preliminary design of high-speed rail (HSR) in Vietnam is an urgent priority during this period. At the same time, the study of modern signaling technology is a crucial factor for operational exploitation, ensuring compatibility with high-speed railways engineered for maximum capacity, safety, and reliability. Accordingly, this paper presents the results of in-depth analysis of train operational headway under specific line constraints, utilizing the Hybrid Level 3 with Trackside Train Detection - Backup (HL3-T) and Hybrid Level 3 with Virtual Sub-Sections (HL3-V) train control signaling within ERTMS/ETCS Level 3. The study implements various operational scenarios based on the line's route plan, as detailed in the project's pre-feasibility study outline. The simulation was performed in MATLAB software programming language, a reliable and widely adopted tool in the scientific community. The research results indicate that, for a modern signaling system operating under the most restrictive conditions (specifically when the estimated headway is simultaneously constrained by the departure, diverging, and converging points), the minimum operational headway between trains on the line within ERTMS/ETCS Level 3 is determined to be 154.3493 seconds (for the HL3-T type) and 152.7640 seconds (for the HL3-V type). These values are consistent with theoretical bases and current technological development trends. The results conclude that ERTMS/ETCS Level 3 is an advanced signaling technology capable of meeting the demands for high capacity and reliable operation necessary for modern HSR exploitation. Based on this robust scientific foundation, ERTMS/ETCS Level 3 is strongly recommended as the optimal solution for deployment in Vietnam.