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The onset and propagation of fractures significantly impact the remaining operational lifespan of locomotive wheels and rail infrastructure, primarily influenced by contact stresses arising from their interaction. This study employs the nonlinear Newton-Raphson algorithm to comprehensively evaluate the structural characteristics and critical regions of the rail-wheel contact-zone. The rail wheel CAD model is developed in the ANSYS-Design_Modeler, and then it undergoes a static structural analysis using its system for this purpose. A comparative analysis between linear and nonlinear approaches through simulation indicates a consistent overestimation of contact parameters–penetration, and frictional stress. In particular, the linear performance analysis shows a penetration value 25 percent lower and frictional stress 6.38 percent less than that of the nonlinear response. This study highlights the importance of nonlinear analysis when it comes to capturing the subtle complexities inherent in actual wheel-rail interactions and reveals the shortcomings of linear analysis in giving correct predictions. The optimization process is conducted on a railway locomotive wheel using the optimal space-filling algorithm of the response surface optimization process. From the optimization process, the effect of each design variable is evaluated and for most of the structural evaluation parameters, tread_width shows a higher sensitivity percentage and therefore has a higher effect as compared to tread_depth. [ABSTRACT FROM AUTHOR]

A pantograph is a key component on the tops of trains that allows them to efficiently tap electricity from power lines and propel them. This study investigates the possibility of using metal matrix composites (MMCs), specifically aluminum MMCs, as a material for making pantograph parts regarding the dynamics of the train's movement and external meteorological conditions. In this study, a computer-aided design (CAD) model is created using PTC Creo design software and moves to detailed finite element analysis (FEA) simulations executed by the ANSYS software suite. These simulations are important in examining how the dynamic performance of pantographs can vary. The incorporation of Al MMC materials into the structure of the pantograph resulted in significant improvements in structural robustness, with equal stress reduced by up to 0.18%. Similarly, aluminum MMC materials reduced the strain energy by 0.063 millijoules. The outcomes not only give a new perspective to the implementation of modern materials but also provide a breakthrough concept to improve efficiency and increase the service life of pantographs. This study marks a significant milestone in the theoretical development of essential train systems, furnishing eminent perspectives toward the tactical development of transportation infrastructure by suggesting new avenues for the smooth incorporation of smart materials in railway transportation, which would contribute to a more sustainable and reliable future. [ABSTRACT FROM AUTHOR]

Gelephu, located in the Himalayan region, has undergone significant development activities due to its suitable topography and geographic location. This has led to rapid urbanization in recent years. Assessing land use land cover (LULC) dynamics and Normalized Difference Vegetation Index (NDVI) can provide important information about urbanization trends and changes in vegetation health, respectively. The use of Geographic Information Systems (GIS) and Remote Sensing (RS) techniques based on various satellite products offers a unique opportunity to analyze these changes at a local scale. Exploring Bhutan's mandate to maintain 60% forest cover and analyzing LULC transitions and vegetation changes using Sentinel-2 satellite imagery at 10 m resolution can provide important insights into potential future impacts. To examine these, we first performed LULC mapping for Gelephu for 2016 and 2023 using a Random Forest (RF) classifier and identified LULC changes. Second, the study assessed the dynamics of vegetation change within the study area by analysing the NDVI for the same period. Furthermore, the study also characterized the resulting LULC change for Gelephu Thromde, a sub-administrative municipal entity, as a result of the notable intensity of the infrastructure development activities. The current study used a framework to collect Sentinel-2 satellite data, which was then used for pre-and post-processing to create LULC and NDVI maps. The classification model achieved high accuracy, with an area under the curve (AUC) of up to 0.89. The corresponding LULC and NDVI statistics were analysed to determine the current status of the LULC and vegetation indices, respectively. The LULC change analysis reveals urban growth of 5.65% and 15.05% for Gelephu and Gelephu Thromde, respectively. The NDVI assessment shows significant deterioration in vegetation health with a 75.11% loss of healthy vegetation in Gelephu between 2016 and 2023. The results serve as a basis for strategy adaption required to examine the environmental protection and sustainable development management, and the policy interventions to minimize and balance the ecosystem, taking into account urban landscape. [ABSTRACT FROM AUTHOR]