Basis for selecting the configuration of high-speed distributed-power trains
Trang: 373-383 Do Duc Tuan, Nguyen Duc ToanTóm tắtIn conventional railways, when utilizing concentrated power, the train configuration is determined based on the locomotive's power and the types of cars used in the train. The total train mass must first be defined for a given limiting gradient. Based on the total train mass and the load and tare weight of the cars, the specific train composition (the number of cars) is determined. For urban rail and high-speed trains, which primarily serve passenger transportation, a different approach is required, particularly for distributed-power trains. In such cases, basic resistance is not calculated separately for each car but for the entire train. The number of cars is typically structured into fixed modules, requiring an assessment of how many motor cars should be included within a given train configuration. To address this issue, the article presents the basis for selecting the configuration of high-speed trains with distributed traction. Based on this, configurations for several different options were selected, and the feasibility of utilizing kinetic energy to overcome limiting gradients along the line was also verified
Two – mode overmodulation technique for inverter in railway vehicle drive systems
Trang: 384-393 Pham Van Tien, Mai Van ThamTóm tắtSource voltage inverters in railway vehicle drive systems often use space vector overmodulation techniques in order to enhance the utilization capability of DC voltage. As a result, this can lead to the expansion of the operating range of traction motors. In this paper, the writer does research on a two-mode space vector overmodulation technique based on the superposition principle between limit trajectories which are applied to two-level voltage source inverters. The advantage of this technique is the ability to maintain linear control in the overmodulation region, which results in low harmonic content in the output AC voltage. In addition, due to its simple control algorithm, it is easy to digitize. The accuracy and the effectiveness of the overmodulation technique are demonstrated by both theoretical analysis and simulation results. The research results indicate that this overmodulation technique is an efficient option when applied to source voltage inverter control in railway vehicle drive systems
Trang: 394-404 Do Duc Tuan, Nguyen Duc ToanTóm tắtThe rolling stock on the Cat Linh - Ha Dong urban railway line, as an independent technical system, is divided into six subsystems: body, running gears, transmission, braking equipment, control, and auxiliary equipment. Reliability evaluation of rolling stock includes many contents such as assessing the reliability of subsystems, cars, and trains; reliability and lifetime of wheelsets due to wear and tear; limiting probabilities when transitioning states of subsystems and rolling stock. The article presents the evaluation of limiting probabilities when transitioning states of subsystems on metro trains in operation on the Cat Linh - Ha Dong line by using the software “Evaluation of the reliability and safety of rolling stock in operation on the Cat Linh - Ha Dong urban railway line”. The calculation results show the most critical elements and subsystems within a specified operational time period, helping users have appropriate solutions in planning spare parts, and replacement materials, reducing downtime for maintenance and repair, and improving the reliability, availability and operating efficiency of rolling stock
Overview of advances and practices in high-speed railway earth structures in China
Trang: 405-419 Tengfei Wang, Nguyen Chau Lan, Bui Tien ThanhTóm tắtHigh-speed railway (HSR) subgrade design and construction technology have advanced significantly in the past decade. This paper outlines these developments in railway earth structures in China, including HSR design principles, subgrade fill classification, subgrade deformation mechanisms, settlement control methods, transition zones, retaining structures, and deformation monitoring analysis and remediation. We present a conceptual framework for design and examine how factors such as track types and operation speeds influence the dynamic response of the subgrade. Furthermore, we discuss prediction methodologies, influential factors, and challenges associated with long-term subgrade deformation. The load transmission mechanisms and application scenarios are evaluated for foundation treatment methods such as geosynthetic-reinforced pile-supported embankment (GRPS) and pile-raft construction. Several retaining structures have been reviewed, including cantilever, geosynthetic reinforced soil, and anchored wall. Finally, innovative construction technologies for subgrade survey, design, construction, detection, and management are introduced
A case study of China on the ballastless track
Trang: 420-431 Tran Viet Hung, Tran Ngoc Hoa, Bui Tien Thanh, Rongshan YangTóm tắtBallastless track systems have become a cornerstone of modern high-speed railway (HSR) infrastructure due to their superior long-term performance, structural stability, and reduced maintenance requirements. This paper provides a comprehensive review of the development and technological innovations in ballastless track structures, with a focused case study on China's experience. The study outlines five major phases in the evolution of ballastless track in China, ranging from early experiments with embedded block track to the importation, adaptation, and eventual independent development of advanced systems such as the CRTS I, II, and III. Through this progression, the paper highlights key innovations in materials, modular design, construction automation, and the integration of smart monitoring technologies. In addition, sustainability aspects such as noise and vibration reduction, use of eco-friendly materials, and lifecycle efficiency are examined. By consolidating technical knowledge and practical insights from China’s large-scale implementation, the paper offers valuable reference for countries considering or planning HSR infrastructure based on ballastless track systems
Effectiveness study on the wind barriers of the HSR bridges in wind prone region
Trang: 432-446 Guo Wei Wei, Xia Chao Yi, Bui Tien ThanhTóm tắtIn areas frequently affected by strong winds, high-speed railway (HSR) bridges are commonly equipped with wind barriers to ensure train operational safety. This study focuses on a multi-span simply supported prestressed concrete bridge located along a real HSR line in Western China. Different barrier configurations with varying heights and porosities are investigated. A comprehensive wind-train-bridge interaction dynamic model is established to simulate the system's response, incorporating the effects of fluctuating crosswind velocities. Temporal histories of dynamic responses from both the train and the bridge are calculated and analyzed. A comparative evaluation of various barrier designs is conducted to determine their effectiveness in mitigating adverse wind effects. The results indicate that a barrier with a total height of 3.5 meters, consisting of 10% porosity in the lower 1.0 meter and 20% porosity in the upper 2.5 meters, provides the best performance in balancing wind shielding and structural stability. This research offers valuable insights for optimizing the design of wind barriers on HSR bridges in high-wind regions
