The railroad facilities are intended for long-term operation as the initial acquisition costs necessary for infrastructure construction are high. Therefore, regular maintenance of railroad facilities is essential, and furthermore, system reliability through systematic performance evaluation is required. In this study, the signal control system of railroad electrical equipment was selected as the subject of research and the performance evaluation target facility selection study was conducted using AHP. The results of the study can contribute to the reliability of the signal control system as well as to the reliability of the railroad system, which is a higher system.
This study developed a flame-retardant fiber-reinforced composite material that satisfies the required regulations of railway vehicle interior parts for the purpose of reducing weight and simplifying the production process using SMC(sheet molding compounds) composite materials. It is essential to secure flame-retardant performance that minimizes flames and smoke for the safe evacuation of passengers in case of fire for interior parts of railway vehicles. In this study, the resin for SMC was developed by adding various flame retardant materials such as vinyl ester (halogen-based and phosphorus-based) and antimony trioxide, and chopped glass fibers were used as the reinforcing material. As a result of preparing specimens for phosphorus-based and halogen-based SMC materials, and comparing the flame retardant performance, the phosphorus-based SMC material had an oxygen index of 36.1, smoke density (1minute 30 seconds, 4minutes, 10minutes) of 1.7, 51.5, 195.1. It was measured with a toxicity index of 0.05 R and average heat for sustained burning of 4.5MJ/m, which satisfies all the flame retardant standards required for interior parts of railway vehicles, and it was found that most of the performance was better than that of halogen-based SMC.
The general contractor business in South Korea settled in the railway construction during the Daehan Empire, but depending on the construction intention and circumstances of the railroad, relationship among employer-contractor-subcontractor and their roles under the system of the construction process had changed. At the time of laying the Gyeongin and Gyeongbu-rail, the Empire, which had no capital and technology, passed all the power and responsibility of the rail laying to the contractor, who was involved in most of the process. After this, the empire tried to lay Gyeongui-railroad without the help of other countries. Japan prepared for the Russo-Japanese War and decided to construct the railway rapidly, and completed the railway in parallel with direct management work and contract work. From that time on, the general contractor would only do the work. During the construction of railroad in Daehan empire, the general contract business system was established. The ambiguous process was sorted out and divided. At this time, subjects in charge of design and construction has been divided. The internal organization of the project owner and the contractor were organaized and specialized.
국내 원자력발전소의 사용후핵연료는 소내저장시설에 보관되어 있으나 저장시설의 용량 확장이 어려움이 있으며, 연구기관 의 연구로에서 발생하는 고준위 방사성폐기물도 자체 보관중이나 영구적으로 저장할 수 없다. 또한 원전의 해체 시에도 고 준위 방사성폐기물이 발생할 것으로 예상된다. 이에 따라, 본 연구에서는 현재 개발된 사용후핵연료 운반용기를 사용하여 고준위 방사성폐기물을 가상의 관리시설로 철도를 통하여 운반하는 경우에 대하여 작업자 및 운반경로 주변 일반인의 예상 피폭선량을 평가하였으며, 그 결과를 국내 법적기준치와 비교하였다. 또한, 고준위 방사성폐기물의 상하차 작업 시 작업자 와 운반용기 간 거리와 운반사고 시 방사성핵종의 누출율의 변화에 따른 피폭선량의 변화에 따른 피폭선량 추이와 운반에 사용되는 열차의 구성에 따른 운반작업자의 피폭선량 변화를 분석하였다. 본 연구에서 설정한 모든 조건에서의 예상피폭선 량은 국내 법적제한치 이하임을 확인하였다.
This paper presents a vibration mitigation method for a railroad station using dual layer TMD (Tuned Mass Damper) technology. The proposed technology can be applied to a platform by installing a spring-damper system between the platform and the railroad station structure. Especially, considering passenger comfort, the technology is developed for not just reducing the vibration of the railroad station structure but minimizing the vibration of the platform. The technology consists of two serially connected masses, and the vibration of the top mass is designed to be minimized, while the bottom mass serves as the platform TMD. The design parameters such as the spring constant and damping coefficient of the dual layer TMD system are optimized using the acceleration response of the structure, at which the platform is installed. The feasibility and performance of the vibration mitigation method is verified via a numerical example of a simple beam structure subjected to a moving load, which can be analogized as a railroad station with a moving train on top. The result of the numerical study shows that the proposed method can effectively reduces the vibration of the top mass as well as the beam structure at the design speed of the moving load.
Recently, measures for reducing noise and vibration of a railroad station are actively being developed to enhance its property value and comfort level of passengers. In this paper, the applicability of the recently developed vibration mitigation method utilizing a platform TMD (Tuned Mass Damper) by installing a spring-damper system beneath the platform is experimentally verified using a bench scale structure. The two-story bench scale structure is built to simulate a real railroad station, and vibration reduction effect is verified by comparing acceleration before and after applying the platform TMD at the 2nd floor of the structure. The design parameters of the platform TMD system is determined based on vibration analysis result and the MTMD (Multiple TMD) theory recently developed to enhance the effectiveness of the platform TMD method. The vibration is excited to the bench-scale structure using a vibrator. The performance test result for a spring-damper system is also presented. The result of the experiment reveals that the platform TMD method can reduce the vibration of the bench-scale structure by greater than 5dB(V).
The study presents technology which can decrease the vibration of railroad station via adopting a friction bearing system beneath a platform. The platform itself then constitutes a tuned mass damper system (TMD) as the bearing provides stiffness and damping of the TMD system. To increase the robustness of the TMD system, the bearing system with adjustable stiffness is utilized. The vibration reduction performance of the TMD system is verified via numerical analysis on an elevated railroad station known as having a structural type with highest noise and vibration level. The numerical analysis is performed using a commercial program, ABAQUS. The vibration analysis is performed considering vehicle-track-structure interaction. The result of the numerical analysis shows that the TMD technology can reduce significant amount of vibration of a railroad station.
Recently, with development of city traffic network planning, there are various effects with living space from vibration of railway. But, study which about effect from vertical vibration in floor slab in nearing structure is lack in nowadays. This thesis have analysed result from acceleration response per distance as well as proceed with serviceability evaluation and extracted natural frequency from measuring vibration of railway using mobile phone application which is oriented for building which have distances about 5m to 22m from railway.
Recently, the Korean government has been making efforts to achieve ‘creative economy’ based on science and technology. As part of these efforts, it has been promoted specific policies for innovation and performance enhancement of national R&D projects. They contains commercialization of research outcomes, technology transfer, technology based startup and support small and medium-sized businesses. The railroad transportation industry is a representative in the field of SOC and has own characteristics different from other industry areas. Especially, industry and market of railroad transportation are directly related to planning and implementation of government SOC policies. So in order to promoting commercialization of railroad transportation projects, it is very important to ensure consistency between government policies and R&D projects. In this paper, we investigate barriers of successful commercialization with typical researchers in the area of railroad transportation, and suggest problems and improvements of policy-based commercialization by giving specific examples.
The train noise and vibration nearby the elevated railway make one specific issue. For the elevated railway, this paper concerns vibration by the bridge. this paper presents vibration level of vibration source of train. The prediction model gives the effects of ground attenuation, and barrier attenuation of noise. The acceleration array method is used to search vibration propagation characteristics of elevated structure to predict the vibration propagation from an elevated railway. Based on the results, this paper proposes the source model of elevated structure-borne vibration and the calculation model for elevated railway vibration. Also measure results are presented with rolling vibration and elevated structure vibration.
본 연구는 감정노동의 연구대상을 좀 더 다양한 산업으로 확대할 필요성이 있어 지금까지 연구되지 않았던 철도여행인솔자 288명을 대상으로 이들의 감정노동을 내면행동과 표면행동으로 구분하여 부정적결과인 감정부조화와 긍정적 결과인 직무만족에 각각 어떠한 영향을 미치는지를 분석하고, 감정노동과 직무만족과의 관계에서 감정부조화의 매개효과와 감정노동과 감정부조화의 관계에서 감정표현규범몰입의 조절효과를 실증 분석하였다. 분석결과를 요약하면 다음과 같다. 우선, 철도여행인솔자의 내면행동은 감정부조화에 부(-)의 영향을, 표면행동은 정(+)의 영향을 미치는 것으로 나타났다. 둘째, 직무만족에 미치는 영향을 분석한 결과, 내면행동은 정(+)의 영향을, 표면행동은 부(-)의 영향을 미치는 것으로 나타났다. 셋째, 감정부조화는 직무만족에 부(-)의 영향을 미치는 것으로 나타났다. 넷째, 감정부조화의 매개효과를 분석한 결과 내면행동과 표면행동 모두 감정부조화를 부분매개하여 직무만족에 유의한 영향을 미치는 것으로 나타났다. 마지막으로 감정표현규범몰입의 조절효과를 분석한 결과, 감정표현규범몰입은 내면행동으로 인한 감정부조화에는 유의한 조절효과를 보이지 않았으나, 표면행동으로 인한 감정부조화는 감소시키는 것으로 나타났다. 이와 같은 연구 결과를 바탕으로 이론적 및 실무적 시사점을 도출하였으며, 향후 연구방향을 제시하였다.
Recently, the quiet fan development is one of important issues for comfort of railroad car. The purpose of this study is to find the vibration and noise source of the line flow fan for reduction the noise level. For a vibration and noise source identification, experiments with microphone and acceleration were carefully carried out. The noise of line flow fan is caused by various factors, such as turbulent flow noise, blade passing frequence and unbalance. In order to reduce the fan noise, the blade shape, distance and angle of housing guide should be modified.
In this paper, two dimensional concrete slabs for a railroad bridge were analyzed by the specially orthotropic laminates theory. Both the geometrical and material property of the cross section of the slab was considered symmetrically with respect to the neutral surface so that the bending extension coupling stiffness, Bij=0, and D16=D26=0. Bridge deck behaves as specially orthotropic plates. In general, the analytical solution for such complex systems is very difficult to obtain. Thus, finite difference method was used for analysis of the problem. In this paper, the finite difference method and the beam theory were used for analysis.
This study is planed to solve the overturning problem and manifestation of tensile cracking of plain concrete piers of railroad bridges. For the overturning problem, earth anchors are used to fix the bottom of a pier to a rock-foundation using prestressing cables. Composite of FRP (Fiber Reinforced Polymer)and Steel Plates (FSP) are attached longitudinally on the surface of the pier to prevent cracking. Then, FRP band strips are wrapped onto the FSPs to provide lateral confinement. Push-over tests in field show that the earth anchors are effective in preventing the overturning of the pier, and that the FSPs and the FRP strips prevent the cracking of concrete and increase the strength in bending.
건물설계단계에서 신축예정건물의 열차진동영향평가를 위하여 국내의 4개의 열차진동 가속도응답 계측치와 진동전달율(Transmissibility)값을 이용한 이론치를 비교하여 TR값의 적용성을 제시하였다. 이 TR 방법을 통하여 철도인접지역 위치한 신축 예정지반을 선정하고 지반진동 계측을 실시하였다. 계측한 지반의 가진진동수와 수직가속도응답과 신축 예정건물의 바닥슬래브를 MIDAS로 해석한 고유진동수를 통해 진동전달률을 산정한 후 신축건물의 진통예측을 실시하였다. TR을 적용한 가속도응답 예측치를 열차진동 가속도응답 계측치와 비교한 결과 3.61%~37.1% 오차범위에서 있는 것을 확인하였다. 또한 KTX, 경의선, 시멘트 열차 주행 시 지반의 가진진동수는 7.19~10.61Hz 사이에 선명한 피크를 확인 할 수 있다.
Korean railway has run about 110 years since 1989 and played a great role of industrialization in Korea. It is known that rail transport systems have many advantages of being more safe, energy-efficient, and environment-friendly, as compared to other tran
The Railroad Safety Act was implemented in 2005 due to the increased concerns regarding railroad safety since the Daegu subway fire in 2003. In line with this, the Act became a standard to build the total railroad safety systems which has been overlooked compared to the quantitative growth of the railroad business. The minister of the ministry of Land, Transportation and Maritime Affairs lays down the Act for railroad Companies to conduct emergency programs in response to the emergency occurring on the railroad such as fire, explosion, derailment, etc. By enacting the Safety Act, the nation's construction of the contingency management system for railroad emergency increased", and it made the railroad company prepare the Emergency SOP by establishing 'The guideline on the Establishment of the railroad Emergency Plan' in order to support the efficiency of the Act. In line with this, I would like to analyze a matter of system development and the main function of the "railroad Emergency Training Program" for activation improvement of standardized operation procedure developed through the 'Total capitalize Safety Technology development'.
This paper analyses the railroad trunk line constructed in the Korea since the end of the 19th century. The analysis consists of the following problematics. 1) The process of the decision of the railroad route 2) The relationship of the location of Eupchi and the stations By clarifying the above, the purpose of this paper is to clarify how the morphology of the city in Korea has been affected by the change in the relationship with Korea and Japan. The Empire of Japan has been reconnoitering the Korea since way before the formal contract for the railroad construction was signed. Therefore, the Empire of Japan had a very good understanding of the actual transportation system when it started the construction of the railroad. The railroad construction was used by the Empire of Japan to empower the control over the Korea. For this reason, the new railroad system was constructed as a different system from the former transportation system and the urban system was also affected. Also the relationship of the western powers and Japan around the turn of the 20th century defined the characteristic of the railway system as a pathway through the Korean peninsular to link Japan to the continent. Moreover, being apprehensive about the friction with the western, Japan located the railway stations to avoid the missionary land properties. This made it clear that the restraint relationship between Japan and the western affected the urban special structure.