Showing papers in "Journal of the Korean Society for Railway in 2012"
TL;DR: In this article, the authors defined the calculation method of GHG emission of railroad was defined with Tier level considering its emission sources to refer to 2006 IPCC guideline for national GHG inventories.
Abstract: Recently, new climate change mechanism after 2020 year has been accepted with the parties, and so government is pushing ahead the GHG reduction policies to achieve the effective results. Especially, it is essential to enhance the role of railroad in the public traffic system as well as to develop new cars with high energy efficiency for the GHG reduction of transportation sector. Thus, the calculation method of GHG emission of railroad should be established to manage the emission continuously. In this study, the calculation method of GHG emission of railroad was defined with Tier level considering its emission sources to refer to 2006 IPCC guideline for national GHG inventories. Also, the GHG emission of railroad at Tier 1 level was investigated using the activity data related to the amount of diesel and electricity consumption from 2008 to 2010. As a result, total GHG emission in 2010 was about 2,060 thousands ton CO2e, which have 73% of electricity and 27% of diesel. In future, the plans on the GHG reduction of railroad will be accomplished by the analysis of the detailed trends on the basis of the emission management of Tier 3 level under operating patterns. Therefore, it is important to develop the specific GHG emission factors of railroad in advance.
13Â citations
TL;DR: In this article, a study on the iron-loss reduction of 110kW-class interior Permanent Magnet Synchronous Motor (IPMSM) for Light Railway Transit (LRT) is conducted.
Abstract: A study on the iron-loss reduction of 110kW-class Interior Permanent Magnet Synchronous Motor (IPMSM) for Light Railway Transit (LRT) is conducted. In general, the iron loss of IPMSM depends on the characteristics of core material and non-oriented electrical steel is used as a core material of IPMSM. In order to reduce the iron-loss of IPMSM, both non-oriented electrical steel and grain oriented electrical steel are applied as core material. Iron loss of 110kW-class IPMSM can be reduced approximately 40% comparing to an existing IPMSM by applying grain oriented electrical steel to the stator teeth.
10Â citations
TL;DR: In this article, a three-dimensional wheelset dynamic analysis is presented in such a way that the precise wheel-rail contact analysis in 3D is implemented into the dynamic equations of a wheelset.
Abstract: Wheelset dynamic analysis is a key element to determine the degree of accuracy of railway vehicle dynamics. In this study, a three-dimensional wheelset dynamic analysis is presented in such a way that the precise wheel-rail contact analysis in three-dimension is implemented into the dynamic equations of a wheelset. A numerical procedure that can be used for the analysis of a wheelset dynamics when the wheel-rail two point contact occurs in a cornering maneuver is developed. Numerical solutions of the constraint equations and the dynamics equations of a wheelset are achieved by using Runge-Kutta method. The proposed wheelset dynamic analysis is validated by comparison against results obtained from VI-RAIL analysis.
10Â citations
TL;DR: In this article, a multibody dynamic analysis is implemented to confirm the safety requirement of the developed high speed train, and railway derailment and lateral guiding force simulation is evaluated according to UIC code 518 OR for international railway vehicle.
Abstract: With the cooperation of many research institutes and railway companies, the next generation high speed train is under development for many years. To confirm the safety requirement of the developed high speed train, multibody dynamic analysis is implemented. Through this analysis, railway derailment and lateral guiding force simulation was evaluated according to UIC code 518 OR for international railway vehicle. Test results were compared by limit value of safety criteria. Safety evaluation results, according to international standards, would provide basic reference data of ensuring safety speed and track radius curve. The safety of the train at the maximum speed is verified by numerical analysis results.
9Â citations
TL;DR: The speed control code deducing in accordance with maximum operation speed and characteristics of rolling stocks was analyzed by analyzing principles of generation of speed control codes allocated in blocks for safe operation, then train operational efficiency was analyze by means of analysis of operation headway.
Abstract: Kyung-Bu High Speed Railway is operated in train control system(tcs) of fixed block operated in a way of dividing track circuits into several blocks in accordance with operation circumstances such as rolling stocks, grade, curves and facilities. The TCS of fixed block system refers to a continuous train control system, which transfers operational information such as entry and exit speed, distance-to-go, and deceleration etc. into on-board train control equipment on the basis of block occupancy of a preceding train. It guarantees a safe operation of trains by giving an emergency braking order, in case that a train exceeds an entry and exit speed of a corresponding block. In this paper, we analyze the speed control code deducing in accordance with maximum operation speed and characteristics of rolling stocks by analyzing principles of generation of speed control code allocated in blocks for safe operation, then train operational efficiency was analyzed by means of analysis of operation headway in accordance with the deduced speed control code. This study will be used to design in case of getting an increase in speed for existing high speed line or new high speed line TCS.
9Â citations
TL;DR: In this paper, the authors analyzed the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction.
Abstract: It is of great importance to assure the running safety, ride comfort and serviceability in designing the floating slab track for mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction. The results of this study demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the dynamic response such as wheel-rail interaction force, rail bending stress and rail uplift force. Hence, it is efficient to decrease the spacing of springs or to increase the spring constants at the transition to obtain the running safety and serviceability. On the other hand, the vehicle body acceleration as a measure of ride comfort is little affected by the discontinuity of the stiffness at the transition, but by the system tuning frequency; thus, to obtain the ride comfort, it is of great significance to select the appropriate system tuning frequency. In addition, the effects of damping ratio, spacing of springs and train speed on the dynamic behavior of the system have been discussed.
9Â citations
TL;DR: In this article, the authors measured the noise of Korean high-speed trains running at different speed from 150 to 300km/h by a microphone array system and derived the relation between maximum sound pressure levels and train moving speeds.
Abstract: In this paper, noise of Korean high-speed trains (KTX) running at different speed from 150 to 300km/h was measured by a microphone array system. From the measurement, relation between maximum sound pressure levels and train moving speeds of KTX was drawn and a regression coefficient from the relation was also derived. Moreover, increases of SPL with speeds of KTX were analyzed in the frequency domain. From the analysis, sound characteristics of passing-by noise of KTX were provided. Then, dominant noise source areas were obtained from the measurements and propagation patterns of KTX in vertical direction were also investigated. Finally, noise sources of KTX were identified from inspection of noise maps.
8Â citations
TL;DR: In this article, the authors analyzed the quality of a commuter rail service of Incheon line 1 with respect to two service measures such as occupancy (crowdedness) and punctuality based on transit smart card data collected in 2009.
Abstract: This study analyzed the quality of a commuter rail service of Incheon line 1 with respect to two service measures such as occupancy (crowdedness) and punctuality based on transit smart card data collected in 2009. In order to analyze the metro services by individual fleet, we aggregated the personal level card data into the fleet operated in each planned schedule. The results show a low level of service for both crowdedness and punctuality during peak hours at the line segment from `Gyeyang` to `International business district`. Further, a close relationship between vehicle occupancy and punctuality is found, which illustrates high passenger demand causes successive metro delay.
8Â citations
TL;DR: In this article, the authors used a small scale derailment simulator and a 1/5 scaled bogie to evaluate the dynamic stability of railway vehicle and wheel/rail interface optimization.
Abstract: The dynamic stability of railway vehicle has been one of the important issues in railway safety. The dynamic simulator has been used in the study about the dynamic stability of railway vehicle and wheel/rail interface optimization. Especially, a small scale simulator has been widely used in the fundamental study in the laboratory instead of full scale roller rig which is not cost effective and inconvenient to achieve diverse design parameters. But the technique for the design of the small scale simulator about the dynamic characteristics of the wheel-rail system and the bogie system has not been well developed in Korea. Therefore, the research using the small-scaled derailment simulator and the 1/5 scaled bogie has been conducted. In this paper, we did running stability test of 1/5 scaled bogie using small-scaled derailment simulator. Also, for the operation of the small scaled simulator, it is required to investigate the performance and characteristics of the simulator system. This could be achieved by a comparative study between an analysis and an experiment. This paper presented the analytical model which could be used for verifying the test results and understanding of the physical behavior of the dynamic system comprising the small- scaled derailment simulator and the 1/5 scaled bogie.
7Â citations
TL;DR: In this paper, a mid-size RC test apparatus equipped with analyzing program is developed that can test samples up to D and can be used to analyze the RC test set up.
Abstract: In this study, a mid-size RC test apparatus equipped with analyzing program is developed that can test samples up to D
7Â citations
TL;DR: Shin-gumho station in Seoul underground subway have been selected to be experimentally investigated and analyzed for the real air supply and exhaust capacity compared to the original capacity of ordinary and emergency condition.
Abstract: Shin-gumho station in Seoul underground subway have been selected to be experimentally investigated and analyzed for the real air supply & exhaust capacity compared to the original capacity of ordinary and emergency condition. The depth of Shin-gumho station is 43.6m which consists of the island-type platform ( floor in underground) and a two-story lobby (first & second floor in underground). An emergency staircase connects between the platform and the lobby. Hot-wire anemometer, capture hood, wind vane & velocity meter and data acquisition systems are employed to perform the automatic measurement in this experiment. For ordinary case, air supply and exhaust capacity in the lobby were reduced by 34% and 46% compared to the original capacity, respectively. Air supply and exhaust capacity in the platform were reduced by 66% and 38%, respectively. For emergency case, air supply in the lobby was reduced by 42% and air exhaust in the platform was reduced by 28% compared to the original capacity. Therefore, air pollution in the station is expected to be worse in the ordinary environment and smoke control capability in the platform will be weakened in case of fire emergency.
TL;DR: In this article, a comparative study on railway accident statistics and various transportation modes is performed, which can be used for the determination of weak areas of railway safety and the level of safety to be achieved.
Abstract: As a result of investment in railway safety since 2004, railway accidents have been reduced by half and we reached a high level of safety compared to other countries. But people are still worries about railway accident, and want safer railway. It is difficult to determine which level of safety must be achieved due to lack of comparative studies on railway safety among different countries and other transportation modes. In this study, a comparative study on railway accident statistics and various transportation modes is performed. The results of this research can be used for the determination of weak areas of railway safety and the level of safety to be achieved.
TL;DR: In this paper, running safety, ride comforts and track acting forces were analyzed and compared by numerical analysis using VAMPIRE program when the vertical and transition curves are superimposed for the ballasted track as well as the concrete slab track.
Abstract: Superimposition of vertical and transition curves is not allowed for all types of tracks in Korean regulation of railway construction. However, this criterion has been established on the basis of difficulty of maintenance of the ballasted track. Comparing with the ballasted track, the concrete slab track has the advantage of maintenance and structural, which allows the superimposition of vertical and transition curves when it satisfies the criteria of running safety and riding comfort. In this study, running safety, ride comforts and track acting forces were analyzed and compared by numerical analysis using VAMPIRE program when the vertical and transition curves are superimposed for the ballasted track as well as the concrete slab track. From the analysis results, it was found that running safety, riding comforts and track acting forces in case of superimposition of vertical and transition curves for the both tracks meet all of the criteria. Therefore, although superimposition of vertical and transition curves for the ballasted track is not allowed because of a lot of maintenance works, it can be applied to the concrete slab track considering the advantage of maintenance and structural safety.
TL;DR: In this article, the authors describe the tail vibration reduction for the next generation high speed EMU(HEMU-430X) using VAMPIRE(railway vehicle dynamic software).
Abstract: This study describes the tail vibration reduction for the next generation high speed EMU(HEMU-430X). Themodel of 6 cars was generated and the calculation was performed using VAMPIRE(railway vehicle dynamic software). Inview of ride characteristics, HEMU-430X was expected to sway at the tail because of the yaw damper direction. The lateralacceleration of vehicle body exceeded the criteria because of hunting. To reduce this hunting motion, some methods suchas wheel profile change, the change of damping coefficient for the 2nd lateral damper, the damping coefficient change ofyaw damper were tested, but had little effect. Finally, the yaw damper direction was changed and the tail vibration disap-peared. In real running test, the tail vibration appeared at the speed of 150km/h and the yaw damper direction change madethe vehicle stable at the speed of 300km/h. The maximum test speed of HEMU-430X is 430km/h. If the tail vibrationappears at higher speed, some other methods in this study may be considered to reduce it.
TL;DR: In this paper, theoretical equations of overturn safety based on multi-body model are derived and analyzed the difference between the result of the solid model and that of multibody model.
Abstract: Rolling stocks are often subjected to the effects of natural strong wind or wind pressure caused by the crossing train. These wind pressure cause the falling-off in running stability and overturn safety. It is sometimes reported that trains are blown over by a gust of wind. So, many countries enact regulations to secure the overturn safety for wind speed. In this study, theoretical equations of overturn safety based on multi-body model are derived and analyzed the difference between the result of the solid model and that of multi-body model. In case of multi-body model, it is assumed that the degrees of freedom for carbody and bogie are assigned an independent values respectively. The results show that the latter approach based on multi-body model can access the overturn safety of train and replace the conventional method by using commercial software which is accessing with decrement of wheel load.
TL;DR: In this paper, the up-lift phenomenon at the bearings installed for railway steel bridges is estimated, and the vertical displacements at mid-span of the bridges are compared according to the bearing types.
Abstract: Dynamic behaviors of line type bearings, spherical bearings and disk bearings which are being used for railway steel bridges are investigated, and that of the bridges is also analyzed. For the purpose, the vertical displacements of the three bearings including fixed and expansion type are measured and analyzed. Also, the deformation of the PTFE plate placed inside of spherical and disk bearings of expansion type is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated and the relationship to the vertical displacement is discussed.
TL;DR: In this article, the authors present an experimental study on the radio propagation characteristics in subway tunnel at 18GHz frequency band which has been assigned to video transmission between train and wayside.
Abstract: This paper presents an experimental study on the radio propagation characteristics in subway tunnel at 18GHz frequency band which has been assigned to video transmission between train and wayside. The radio propagation tests are carried out in the subway tunnel of Seoul Metro using the antenna and communication devices of the prototype video transmission system. The measurement results show that 18GHz radio propagation in subway tunnel has smaller path loss than that of general outdoor radio environment. It is also cleared that the arch-type tunnels have smaller radio propagation losses than rectangular tunnels, and single track tunnels have smaller pass loss than double track tunnels. From the measurements, the radio propagation coverage is worked out as 520 meters. The curved tunnels which cannot have LOS communication between transmitter and receiver have large pass losses and fluctuation profile along distance. The radio propagation coverage along curved tunnels is worked out as 300 meters. These investigation results can be used to design the 18GHz radio transmission system for subway tunnel by providing the optimized wayside transmitter locations and handover algorithm customized to the radio propagation characteristics in subway tunnels.
TL;DR: In this article, the aerodynamic noise characteristics of high-speed trains were deduced from the beamforming method by measuring pass-by noise of high speed trains by a microphone array system.
Abstract: In this paper, aerodynamic noise characteristics of high-speed trains were deduced from the beamforming method. First, pass-by noise of high-speed trains was measured by a microphone array system. This measurement suggested that the majority of the aerodynamic noise produced came from the bogie area, the pantograph and its cover, and inter-coach gaps. Then, beampower outputs of a position in high-speed trains were obtained from the beamforming method. By Fourier transform, sound characteristics of the position in the frequency domain were deduced from the beamforming power spectrum. From this study, aerodynamic noise characteristics from the major sources of high-speed trains were drawn.
TL;DR: In this paper, the authors proposed a sound insulation strategy in the tunnel for the next generation high speed train under development and measured the intensity transmission loss according to ASTM E2249-02.
Abstract: In a tunnel, interior noise of a high speed train increases by 5dB~7dB. The reason is that the sound intensity of the acoustic field in the tunnel significantly increases by the reflected waves occurred in the closed space. Especially, the incident acoustic power largely increases on the outside of the compartment side panel and large transmission of noise is available through the side panel and the glass window. In this paper, the sound insulation strategy in the tunnel is proposed for the next generation high speed train under development. Specimens of the aluminum extruded panels, layered panels and double glazed window are manufactured and intensity transmission loss is measured according to ASTM E2249-02. Based on the measured data, problems in the sound insulation performance are diagnosed and the sound insulation strategy is reviewed on each panel and layered structures.
TL;DR: In this article, the authors developed the characteristics method analysis based on fixed mesh system and compared with the results of real train test to analyze the transient pressure phenomena in tunnel qualitatively and quantitatively, because pressure change rate is considered as one of major design parameters for an optimal tunnel cross sectional area and the repeated fatigue force on car body.
Abstract: Pressure waves are generated and propagate in tunnel when train enters a tunnel with high speed. Compression wave due to the entry of train head propagates along the tunnel and is reflected at tunnel exit as expansion wave. While expansion wave due to the entry of train tail propagates along the tunnel and is reflected at tunnel exit as compression wave. These pressure waves are repeatedly propagated and reflected at tunnel entrance and exit. Severe pressure change per second causes ear-discomfort for passengers in cabin and micro pressure wave around tunnel exit. It is necessary to analyze the transient pressure phenomena in tunnel qualitatively and quantitatively, because pressure change rate is considered as one of major design parameters for an optimal tunnel cross sectional area and the repeated fatigue force on car body. In this study, we developed the characteristics method analysis based on fixed mesh system and compared with the results of real train test. The results of simulation agreed with that of experiment.
TL;DR: In this paper, the authors investigated the static and dynamic behaviors of railway bridge with concrete track through experimental study, and numerical analysis was performed about considering only mass of concrete track and together with stiffness and mass effects for concrete track.
Abstract: Precise estimation f a structure`s dynamic characteristics is indispensable for ensuring stable dynamic response during life time especially for the structures which can experience resonance such as railway bridges. Especially, concrete track can change the modal properties of the railway bridge, through the contribution of stiffness as well as mass effects, generally only the mass effect is considered in dynamic analysis of the railway bridge. In this paper, static and dynamic behaviors of railway bridge with concrete track were investigated through experimental study. Also, numerical analysis was performed about considering only mass of concrete track and together with stiffness and mass of concrete track. These were compared with experiment value. Numerical analysis value considering together with stiffness and mass of concrete track was similar experiment value. Therefore, when dynamic analysis of railway bridge with concrete track is performed, the contribution of stiffness as well as mass effects for concrete track is considered.
TL;DR: In this paper, an optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor was proposed to reduce the core losses and improve the performance of the motor.
Abstract: Interior Permanent Magnet Synchronous motors (IPMSM) with concentrated winding are superior to distributed winding in the power density point of view. But it causes huge amount of eddy current losses on the permanent magnet. This paper presents the optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor to reduce the core losses and improve the performance. Each eddy current loss on permanent magnet has been investigated in detail by using FEM (Finite Element Method) instead of equivalent magnetic circuit network method in order to consider saturation and non-linear magnetic property. Simulation-based design of experiment is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, it is verified by FEM.
TL;DR: In this article, a laboratory mock-up test has been performed, and the static and dynamic behaviors at frequency range near the system resonance frequency were explored based on the test results, the design of the floating slab track and the structural analysis model used in the design have been verified.
Abstract: Recently, with increasing social interests on noise and vibration induced by railway traffic, the application of floating slab track that can efficiently reduce the railway vibration is increasing. In this study, to more accurately understand the dynamic behavior of the floating slab track, a laboratory mock-up test has been performed, and the static and dynamic behaviors at frequency range near the system resonance frequency were explored. Based on the test results, the design of the floating slab track and the structural analysis model used in the design have been verified. The analytic and test results demonstrate that the dominant frequency of the floating slab track occurs at the frequencies between vertical rigid body mode natural frequency and bending mode natural frequency, and the dominant deformation mode is close to the bending mode. This suggests that in the design of the floating slab track, the bending rigidity of the slab and the boundary conditions at slab joints and slab ends should be taken into consideration. Also, the analytic results by the two-dimensional finite element analysis model using Kelvin-Voigt model, such as static and dynamic deflections and force transmissibility, are found in good agreement with the test results, and thus the model used in this study has shown the reliability suitable to be utilized in the design of the floating slab track.
TL;DR: The HEMU-430X is a world-class railway vehicle which aimed the maximum speed of 430km/h and the operation speed of 370 km/h as mentioned in this paper.
Abstract: The HEMU-430X is a world-class railway vehicle which aimed the maximum speed of 430km/h and the operation speed of 370km/h. To maintain high-speed operation condition over 300km/h, various requirements for satisfy exist. However, one of the most important things is a reliable supply of electricity. Especially, the dynamic interaction between the pantograph and overhead contact line at high-speed is a significant matter to pre-evaluate. In this paper, using the dynamic interaction analysis program, current collection performance of the HEMU-430X was investigated. Firstly, based on the international standard, performance of the original specifications was evaluated. In addition, through study on changes in tension and span length, improvement of the performance was considered.
TL;DR: In this article, a single degree of freedom hybrid test was performed with one-bay, two-story steel frame structure and one column at the first floor was selected as a physical substructure and one actuator was used for applying the displacement load in horizontal direction.
Abstract: The purpose of this study is to evaluate the structural dynamic behavior under hybrid control system. The hybrid test is to consider the interaction between the numerical and physical models. In this paper, single degree of freedom hybrid test was performed with one-bay, two-story steel frame structure. One column at the first floor was selected as a physical substructure and one actuator was used for applying the displacement load in horizontal direction. El Centro as earthquake waves was inputted and OpenSees was employed as the numerical analysis program for the hybrid real-time simulation. As a result, the total time of the hybrid test was about 9.6% of actual measured seismic period. The experimental results agreed well with the numerical one in terms of the maximum displacement. In nonlinear analysis, however, material nonlinearity made a difference of residual strain. Therefore, this hybrid dynamic test can be used to predict the structural dynamic performance more effectively than shaking table test, because of the spatial and economic limitations.
TL;DR: In this paper, the authors presented the ERRI design diagrams of KTX and HEMU applicable to simply supported single span bridges, and analyzed the dynamic characteristics and design considerations of the bridges under KTX/HEMU using the diagrams.
Abstract: This paper presents the ERRI design diagrams of KTX and HEMU applicable to simply supported single span bridges, and analyzes the dynamic characteristics and design considerations of the bridges under KTX and HEMU using the diagrams. The design diagrams of KTX and HEMU are calculated for the bridges with 25m, 30m, 35m and 40m span lengths, which are widely used for simple bridge in Korea. From the design diagrams, the dynamic characteristics of the bridges with the selected span lengths are analyzed. In addition, the design consideration is discussed to satisfy the design requirement of acceleration. It is desirable for the bridge with 25m span length to avoid resonance both for KTX and HEMU. Since larger responses are expected for HEMU in the bridge with 30m span length, and for KTX in the bridge with 35m and 40m span length, the bridges should be planned to have enough mass satifying acceleration requirement at resonance, or to avoid the resonance.
TL;DR: In this paper, the authors analyzed the effects of the KTX driver's person-environment fit on job satisfaction, organizational commitment and turnover intention, and examined the mediating effect of job satisfaction and organizational commitment.
Abstract: This study analyzes the effects of the KTX driver`s person-environment(job, organization, Coworker) fit on job satisfaction, organizational commitment and turnover intention. It, additionally, examines the mediating effect of job satisfaction and organizational commitment between person-environment fit and turnover intention. Consequence of the analysis indicates that person-environment fit has mostly meaningful influences on job satisfaction, organizational commitment and turnover intention. But person-job fit makes a meaningless impact on job satisfaction, and person-coworker fit also makes a meaningless impact on job satisfaction and turnover intention. The mediating effect of job satisfaction and organizational commitment is mostly effective, but the mediating effect of job satisfaction does not affect the relation between person-organization fit and turnover intention. In conclusion, this study implies that, in order to grasp KTX driver`s turnover intention and to protect actual turnover, it is important to enhance job satisfaction and organizational commitment as well as to improve overall person-environment fit.
TL;DR: In this article, the authors evaluated how depth of hardening on rail surface is formed and suggested optimal rail grinding amount by RCF(rolling contact fatigue) test with generated contact pressure between KTX wheel and UIC60 rail by applying FEM analysis.
Abstract: The rail surface defects which are generated on repeated rolling contact fatigue are getting increased according to high speed, high density, and minimum weight. In addition, Increasing noise and vibration are affected by these also impact load generated as well. Because of this phenomenon, more serious and critical damages were occurred. In fact, in order to control them, the rail grinding amount in Korea. This study evaluated how depth of hardening on rail surface is formed and suggested optimal rail grinding amount by RCF(rolling contact fatigue) test with generated contact pressure between KTX wheel and UIC60 rail by applying FEM analysis. Therefore, the amount was generated approximately 0.2mm/20MGT to maintain integrity of rail surface by getting rid of depth of hardening on rail according to rail accumulated passing tonnage.
TL;DR: In this article, Sosa station, semisealed screen door and EMU are analyzed to estimate the wind pressure of platform screen doors model under the worst weather condition such as typhoon.
Abstract: Installation of screen doors at platform ensures safety of passengers by separating platform from tracks. Besides, it reduces drought and air pressure caused by train conserves heating and cooling energy in the station. In order to guarantee safety of platform screen doors, design considering evaluation of wind pressure requires. In this study, Sosa station, semisealed screen door and EMU are analyzed to estimate the wind pressure of platform screen doors model. Also Sosa station is influenced by climatic condition because it exposed to outside. Therefore, analysis on the wind pressure of platform screen doors is performed under the worst weather condition such as typhoon. The results of analysis, Maximum inside pressure 287 Pa, and consideration of outside pressure as typhoon to the maximum design pressure of 865 Pa 2756.25 Pa conditions approximately 3.1 times the difference can be seen that ensure stability.
TL;DR: In this article, the authors investigated the properties of Japanese colonial period railway and found that the railway was built mainly for military purposes by Japan and after the annexation by Japan, it became a means of colonization for Japan but the railway also promoted modernization.
Abstract: At first, the railway was built mainly for military purposes by Japan. After the annexation by Japan, the Korean railway became a means of colonization for Japan but the railway also promoted modernization. As a new transportation medium, it influenced economic, cultural and social development. Until now, research identifying the properties of the railway in the Japanese colonial period has been insufficient. In particular, microscopic study of the influence of the railway on social change has been insufficient. In this study we investigated the properties of Japanese colonial period railway. This paper will help further to clarify the properties of the railway in the Japanese colonial period.