Browse Topic: Heavy rail systems

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Research on Risk Analysis of Emergencies in Heavy-Haul Railway Operations Based on Knowledge Graph2025-99-034712/17/2025
Heavy-haul railways are a critical component of China’s dedicated freight rail network, serving as the primary land transport channel for energy and resource intermodal transportation. Their safe operation and transportation is essential for ensuring the reliable delivery of energy and raw materials. Taking the Shuohuang Heavy-haul Railway as a case study, based on the hazards identified across its entire operational chain, an ontology model structured as "professional module–task–process–hazard–risk attribute–management object" is constructed in this paper. Based on this model, a knowledge graph for heavy-haul railway operational emergencies is established. The study analyzes the connectivity between different nodes (e.g., work processes and hazards) in the knowledge graph and their potential relationships with risk values. Using directed graph-based degree centrality analysis, a risk assessment method incorporating node centrality is proposed. Risk values are computed at both the hazard and process levels, followed by risk ranking and analysis. The risk ranking results demonstrate that considering node centrality yields rankings that better reflect the complex division of labor in heavy-haul railway transportation system, thereby providing more effective support for emergency risk management. The research results can provide decision-making support for the prevention and control of emergencies in heavy-haul railway operations, as well as safety management.
Fu, Liqiang, Ren, Xiaolin, Rong, Lifan
Low-Temperature Coolant Circuit Nomenclature and ApplicationsJ3136_202506 (Current)6/17/2025
The document provides clarity related to multiple temperature coolant circuits used with on-highway and off-highway, gasoline, and light-duty to heavy-duty diesel engine cooling systems, or hybrid vehicle systems. These multiple temperature systems include engine jacket coolant plus at least one lower temperature system. Out of scope are the low temperature systems used in electric vehicles. This subject is covered in SAE J3073. Note that some content in SAE J3073 is likely to be of interest for hybrid vehicles. Out of scope are the terms and definitions of thermal flow control valves used in either low-temperature or high-temperature coolant circuits. This subject is covered in SAE J3142.
Cooling Systems Standards Committee
FEA Stress Determination for Weld Fatigue using Hot-Spot Stress Method: Benchmarking and Rail ApplicationSAE-PP-003945/5/2024
Welded joints in rail steel structures are typically assessed for fatigue using two different stress range approaches: nominal stress range and hot-spot stress range when using SN methods. The nominal stress range is a traditionally simplified method that provides a conservative estimation but lacks accuracy in considering stress concentrations. On the other hand, the hot-spot stress range method is a more advanced and refined approach that offers a more precise evaluation of stress concentration, making it suitable for complex geometries. In 2015, the British standard BS7608-2015 on Guide to Fatigue Design and Assessment of Steel Products incorporated the hot-spot method for evaluating weld joints, especially when using numerical methods as Finite Element Analysis (FEA). The weld classes are now categorically defined for both nominal and hot-spot approaches in new introductions, whereas earlier, it was based on the nominal stress approach only. Choosing the appropriate stress range method depends on various factors, including the weld joint's geometry, stress orientations, loading conditions, the desired level of accuracy, and primarily the available SN curve data for predicting fatigue damage. The work presented in this paper explores the hot-spot stress range approach for determining stress ranges in weld fatigue assessment for Rail Track Maintenance Equipment. The identified welds were evaluated and compared for fatigue stress ranges using IIW and BS7608 guidelines for the hot-spot stress approach. The effect of various mesh types and finite element (FE) modeling on peak and structural stress was studied and presented. Subsequently, the hot-spot approach was applied to assess the weld fatigue in rail equipment, and the results were compared with those obtained using the nominal stress approach.
Patil, Dipak
Weld Fatigue Damage Assessment of Rail Track Maintenance Equipment: Regulatory Compliance and Practical Insights05-17-02-00103/4/2024
The use of appropriate loads and regulations is of great importance in weld fatigue assessment of rail on-track maintenance equipment and similar vehicles for optimized design. The regulations and available loads, however, are often generalized for several categories, which proves to be overly conservative for some specific categories of machines. EN (European Norm) and AAR (Association of American Railroads) regulations play a pivotal role in determining the applicable loads and acceptance criteria within this study. The availability of track-induced fatigue load data for the cumulative damage approach in track maintenance machines is often limited. Consequently, the FEA-based validation of rail track maintenance equipment often resorts to the infinite life approach rather than cumulative damage approach for track-induced travel loads, resulting in overly conservative designs. The work presented in this article evaluates and compares the weld fatigue damage of track maintenance equipment for EN loads using infinite life approach and AAR loads using cumulative damage approach and highlights the need of having distinct category for track maintenance machines in regulations based on its usage and application to have close representative loads for the endurance limit approach or suitable loads for the cumulative damage approach. Additionally, the study utilizes the BS7608 regulation to determine weld class and predict weld fatigue damage. Both nominal and hot-spot stress approaches are employed to thoroughly investigate and calculate fatigue damage, providing a comprehensive analysis of weld fatigue in rail maintenance equipment.
Patil, Dipak, Petersen, Michael
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