• Title, Summary, Keyword: Railway vehicle

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Experimental Study on the Fatigue Strength of a Running Equipment in Railway Applications (철도적용에서 구동장치의 피로강도에 관한 시험적 연구)

  • Yoon, Sung Cheol;Kim, Jeongguk
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.9
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    • pp.739-744
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    • 2016
  • The truck that is used as running equipment for tank freight car support is a core structural part that supports the load of the car body and significantly influences the safety of freights and vehicles, as well as their running performance. Running equipment is composed of truck frames, wheels and wheel axles, independent suspensions, and brakes. Among these components, the truck frame supporting the load of the vehicles and freights may be the most important component. This study was carried out to analyze the structure of truck frames and to determine whether they are safe when the maximum vertical load, braking part load, and the front and rear load are applied to truck frames. This was achieved by subjecting the truck frames to stress tests and then measuring the stress on each part. The results of the stress tests showed that truck frames have a safe vehicle load design.

A Study on the Maintenance Policy Considering the Failure Data of the EMU Braking System and the Cost Function (전동차 제동장치의 고장데이터와 비용함수를 고려한 유지보수 정책에 관한 연구)

  • Han, Jae-Hyun;Kim, Jong-Woon;Koo, Jeong-Seo
    • Journal of the Korean Society of Safety
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    • v.30 no.3
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    • pp.13-19
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    • 2015
  • Railway vehicle equipment goes back again to the state just before when failure by the repair. In repairable system, we are interested in the failure interval. As such, a statistical model of the point process, NHPP power law is often used for the reliability analysis of a repairable system. In order to derive a quantitative reliability value of repairable system, we analyze the failure data of the air brake system of the train line 7. The quantitative value is the failure intensity function that was modified, converted into a cost-rate function. Finally we studied the optimal number and optimal interval in which the costs to a minimum consumption point as cost-rate function. The minimum cost point was 194,613 (won/day) during the total life cycle of the braking system, then the optimal interval were 2,251days and the number of optimal preventive maintenance were 7 times. Additionally, we were compared to the cost of a currently fixed interval(4Y) and the optimum interval then the optimal interval is 3,853(won/day) consuming smaller. In addition, judging from the total life, "fixed interval" is smaller than 1,157 days as "optimal interval".

A study on the acoustic performance test method using speaker of a noise reduction device for noise reduction of the 400km/h class high-speed railroad (스피커를 이용한 400km/h급 고속철도 소음저감용 방음벽 상단장치의 음향성능 시험방법에 관한 연구)

  • Yoon, Je-Won;Kim, Young-Chan;Jang, Kang-Seok;Eum, Ki-Young;Jang, Seung-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.625-629
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    • 2014
  • For the purpose of the acoustic performance evaluation of noise reduction device(NRD) installed at the top of noise barrier for further decreasing of noise level of 400km/h class high-speed railroad(HEMU), the acoustic performance test method using speaker instead of really running railway vehicle was suggested in this paper. For this, noise source location and frequency spectrum of HEMU was analyzed through the field noise test. These data were used for the determination of speaker's installation positions and frequency correction values applied to the speaker noise source. And, 400 meters long NRD was installed at the site where HEMU will be running at a speed of 400km/h. Finally, the outdoor speaker test with and without NRD showed that this NRD could decrease noise level even more than 3dB(A). In the future, the acoustic performance results of NRD conducted with speaker test will be compared with that of field test for HEMU running at a speed of 400km/h.

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The Study on Correction Factor of a Small Scale Reverberation Chamber to Estimate Transmission Loss (소형 잔향실의 확산 음장 보정 계수 측정 연구)

  • Kim, Tae Min;Kim, Da Rae;Kim, Jeung Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.960-965
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    • 2014
  • Transmission loss of specimen is calculated by measuring energy of incident and transmission and using reverberant room of large size. But normal measurement of transmission loss has trouble because it is actually demanded that large area and specimen of certain size is satisfied with condition of diffused sound field. Especially, in case of mechanical component, interested frequency band is mid-frequency band between 500 ~ 2k Hz, and it is used to be available to minimize a reverberation chamber under conditions satisfying acoustic one because production of specimen for transmission loss measurement has limit. But, as in semi-reverberation room, it is difficult to satisfy condition of diffuse sound field and modification factor is applied to complement that. Correction factor when measuring transmission loss using semi-reverberation chamber is required accuracy because it works as main factor determining reliability of reuslts on transmission loss. In this study, it is analyzed that an effect on correction factor based on varying materials and sizes of specimens in order to deduction of it. Also It is confirmed that applied by elicited correction factor with actual railway vehicle's floor has reliability.

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A framework for carrying out train safety evaluation and vibration analysis of a trussed-arch bridge subjected to vessel collision

  • Xia, Chaoyi;Zhang, Nan;Xia, He;Ma, Qin;Wu, Xuan
    • Structural Engineering and Mechanics
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    • v.59 no.4
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    • pp.683-701
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    • 2016
  • Safety is the prime concern for a high-speed railway bridge, especially when it is subjected to a collision. In this paper, an analysis framework for the dynamic responses of train-bridge systems under collision load is established. A multi-body dynamics model is employed to represent the moving vehicle, the modal decomposition method is adopted to describe the bridge structure, and the time history of a collision load is used as the external load on the train-bridge system. A (180+216+180) m continuous steel trussed-arch bridge is considered as an illustrative case study. With the vessel collision acting on the pier, the displacements and accelerations at the pier-top and the mid-span of the bridge are calculated when a CRH2 high-speed train running through the bridge, and the influence of bridge vibration on the running safety indices of the train, including derailment factors, offload factors and lateral wheel/rail forces, are analyzed. The results demonstrate that under the vessel collision load, the dynamic responses of the bridge are greatly enlarged, threatening the running safety of high-speed train on the bridge, which is affected by both the collision intensity and the train speed.

The study on scheme for train position detection based on GPS/DR (GPS/DR기반의 차상열차위치검지방안 연구)

  • Shin, Kyung-Ho;Joung, Eui-Jin;Lee, Jun-Ho
    • Proceedings of the KSR Conference
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    • pp.802-810
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    • 2006
  • For a thorough train control, the precise train position detection is necessarily required. The widely used current way for train position detection is the one of using track circuits. The track circuit has a simple structure, and has a high level of reliability. However trains can be detected only on track circuits, which have to be installed on all ground sections, and much amount of cost for its installation and maintenance is needed. In addition, for the track circuit, only discontinuous position detection is possible because of the features of the closed circuit loop configuration. As the recent advances in telecommunication technologies and high-tech vehicle-based control equipments, for the train position detection, the method to detect positions directly from on trains is being studied. Vehicle-based position detection method is to estimate train positions, speed, timing data continuously, and to use them as the control information. In this paper, the features of GPS navigation and DR navigation are analyzed, and the navigation filters are designed by constructing vehicle-based train position detection method by combining GPS navigation and DR navigation for their complementary cooperation, and by using kalman filter. The position estimation performance of the proposed method is also confirmed by simulations.

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An Experimental Study on the Longitudinal Resistance Behavior of an Existing Ballastless Steel Plate Girder Bridge (기존 무도상 판형교 궤도의 종저항거동에 대한 실험)

  • Kim, Kyoungho;Hwang, Inyoung;Baek, Inchul;Choi, Sanghyun
    • Journal of The Korean Society For Urban Railway
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    • v.6 no.4
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    • pp.327-337
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    • 2018
  • Since the track of the ballastless steel plate girder bridge is connected to a main girder without a deck and a ballast, the impact generated by train passage is transferred directly to bridge main members, and it can cause frequent damage of the bridge as well as higher noise and vibration level. Applying the CWR (Continuously Welded Rail) technology can reduce this structural problems, and, to this end, it is necessary to understand the characteristics of factors influencing vehicle-track or track-bridge interaction. In this paper, experimental study results are presented for examining the longitudinal resistance characteristics of the track, including a rail fastener, a sleeper fastener, and a track skeleton, installed on a ballastless steel plate girder bridge. The experiment is conducted using a disposed bridge from service, which is transported to a laboratory. The experimental results show that the rail fastener satisfies the performance criteria of the longitudinal resistance presented in KRS TR 0014-15, and the longitudinal resistance of old and new type sleeper fasteners is higher than the values provided in the existing research. Also, the unloaded longitudinal resistance of the ballastless track is between the ballast and the concrete tracks.

Research on Vibration and Noise Characteristics of Steel Plate Girder Bridge with Embedded Rail Track System (레일매립궤도 시스템이 적용된 판형교의 진동 및 소음특성에 대한 연구)

  • Park, Jeung-Geun;Koh, Hyo-In;Kang, Yun-Suk;Jeong, Young-Do;Yi, Seong-Tae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.1
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    • pp.94-101
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    • 2019
  • Most of the existing rail structures have undergone a lot of aging since a considerable period of time has passed from completion. In particular, among existing railway bridges, many of the plate girder bridges are older bridges that have lived 40 to 60 years or more. Since the treadmill is directly connected to the girder without the ballast, the running load of the vehicle is directly transmitted to the bridge. Therefore, the shock and noise applied to the bridge are larger than those of the ballast bridge, and the dynamic shock and vibration are also relatively large. Therefore, it is very urgent to develop appropriate maintenance, repair and reinforcement technology for existing steel plate bridge. In this study, the authors introduced the characteristics of embedded rail (ERS) developed for improving the performance of the existing plate girder bridge and the techniques solving the vibration and noise problems. In order to evaluate the vibration and noise reduction performance of ERS, a non-ballast plate girder bridge with 5m length of sleepers installed and a plate girder bridge with ERS were fabricated. And, then, the vibration response generated under the same excitation condition was measured and analyzed. Also, the radiated noise analysis was performed using the vibration response data obtained from the experiment as the input data of the acoustic analysis model. As a result of experiments and analyses, it was confirmed that the plate girder bridge's vibration using ERS was reduced by 15.0~18.8dB and the average noise was reduced by 7.7dB(A) more than the non-ballast bridge.

Study on Forecasting Urban Rail Demand Reflecting Transfer Fare Value in a Non-integrated Fare System (독립.환승할인요금체계하의 환승요금가치를 고려한 도시철도 수요추정 연구)

  • Lee, Jong-Hun;Son, Ui-Yeong
    • Journal of Korean Society of Transportation
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    • v.27 no.5
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    • pp.155-162
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    • 2009
  • The recent increase of light rail construction by the private sector in Korea has caused a new issue in forecasting rail demand. Integrated fare systems between several rail operators is convenient and brings cost savings to users, and therefore is also very effective in increasing demand. However, it causes some short-term revenue loss to operators so that the private sector often suggests a non-integrated fare system. The current rail demand forecasting model is based upon an integrated fare system. Thus this model cannot be used to forecast the demand with a non-integrated fare system. Some value of transfer fare should be estimated and applied to forecast the demand in a non-integrated fare system. This study conducted a stated preference (SP) survey on urban railway passengers and estimated the value of transfer fare. The estimated value is 2,609 Won/hr, which is about 52% of in-vehicle time. This shows railway users have a tendency to pay more for transfer fares to save time or distance. This value has some limitations since it is derived from the SP survey. If some non-integrated fare system is applied in the future and a RP survey is conducted and compared with these study results, a more clear value of the transfer fare will be derived.

Serviceability Assessment of a K-AGT Test Bed Bridge Using FBG Sensors (광섬유 센서를 이용한 경량전철 교량의 사용성 평가)

  • Kang, Dong-Hoon;Chung, Won-Seok;Kim, Hyun-Min;Yeo, In-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.4
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    • pp.305-312
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    • 2007
  • Among many types of light rail transits (LRT), the rubber-tired automated guide-way transit (AGT) is prevalent in many countries due to its advantages such as good acceleration/deceleration performance, high climb capacity, and reduction of noise and vibration. However, AGT is generally powered by high-voltage electric power feeding system and it may cause electromagnetic interference (EMI) to measurement sensors. The fiber optic sensor system is free from EMI and has been successfully applied in many applications of civil engineering. Especially, fiber Bragg grating (FBG) sensors are the most widely used because of their excellent multiplexing capabilities. This paper investigates a prestressed concrete girder bridge in the Korean AGT test track using FBG based sensors to monitor the dynamic response at various vehicle speeds. The serviceability requirements provided in the specification are also compared against the measured results. The results show that the measured data from FBG based sensors are free from EMI though electric sensors are not, especially in the case of electric strain gauge. It is expected that the FBG sensing system can be effectively applied to the LRT railway bridges that suffered from EMI.