• Title, Summary, Keyword: Railway operation indexes

Search Result 6, Processing Time 0.04 seconds

Safety Evaluation of Elevated Guideway during Abnormal Operation on LRT of Driverless Automatic Driving System (무인자동운전 경전철시스템 고가교량의 비상운전 중 안전성평가)

  • Son Eun-Jin;Kim Min-Soo;Lim Young-Su;Lim Jong-Pil
    • Journal of the Korean Society for Railway
    • /
    • v.9 no.1
    • /
    • pp.29-35
    • /
    • 2006
  • Trains in LRT(Light Railway Transit) system usually have shorter car length than metro's because of their smaller passensers demand. Therefore it is very likely that the load condition of LRT system in abnormal operation, in case of which trains are in close proximity by system broke or train rescue works, could be worse rather than in normal operation, in spite of rare probability of abnormal operation. In this study, the target reliability indexes of several abnormal operations are estimated in accordance with the occurrence probabilities of each abnormal operation case and the reliability index of normal operation presented by the specification. From the indexes, load factors for the abnormal operation cases are estimated and the safety evaluation is performed for Yong-in LRT project.

Risk identification, assessment and monitoring design of high cutting loess slope in heavy haul railway

  • Zhang, Qian;Gao, Yang;Zhang, Hai-xia;Xu, Fei;Li, Feng
    • Structural Monitoring and Maintenance
    • /
    • v.5 no.1
    • /
    • pp.67-78
    • /
    • 2018
  • The stability of cutting slope influences the safety of railway operation, and how to identify the stability of the slope quickly and determine the rational monitoring plan is a pressing problem at present. In this study, the attribute recognition model of risk assessment for high cutting slope stability in the heavy haul railway is established based on attribute mathematics theory, followed by the consequent monitoring scheme design. Firstly, based on comprehensive analysis on the risk factors of heavy haul railway loess slope, collapsibility, tectonic feature, slope shape, rainfall, vegetation conditions, train speed are selected as the indexes of the risk assessment, and the grading criteria of each index is established. Meanwhile, the weights of the assessment indexes are determined by AHP judgment matrix. Secondly, The attribute measurement functions are given to compute attribute measurement of single index and synthetic attribute, and the attribute recognition model was used to assess the risk of a typical heavy haul railway loess slope, Finally, according to the risk assessment results, the monitoring content and method of this loess slope were determined to avoid geological disasters and ensure the security of the railway infrastructure. This attribute identification- risk assessment- monitoring design mode could provide an effective way for the risk assessment and control of heavy haul railway in the loess plateau.

Calculating and Improving Operational Decision-Making Indices for Public Railways by Inclusion of Non-economic Factors (비경제성 요소를 포함한 철도운행 의사결정을 위한 지표 산정 및 개선에 관한 연구)

  • Yang, Jungyu;Ha, Ohkeun;Kim, Ikhee
    • Journal of the Korean Society for Railway
    • /
    • v.16 no.1
    • /
    • pp.65-70
    • /
    • 2013
  • In many cases, operation of regional trunk lines is not profitable to railway operators. Nevertheless, railway operators are under pressure to manage regional trunk lines running under deficits, to better serve public interests. Given this situation, railway operators need to optimize assets by adjusting train schedules or changing the number of trains running. When railway operators judge the operation of a regional trunk line, the B/C ratio is generally used as a management index. This ratio is not considered part of strategic operational policy over the long term, and excessively influenced by the aspects of supply and demand over the short term. Accordingly, this study focused on indices that might be used to prevent worsening deficits and provide long term strategic operation policies, main indices to better measure economic situations, and auxiliary indices to supplement the main index. The main indices were measured in conventional ways to target experts and employees. This study presents quantitative standards, which are intended to be used to create itemized criteria through an Analytic Hierarchy Process, for better decision-making.

Power Quality Optimal Control of Railway Static Power Conditioners Based on Electric Railway Power Supply Systems

  • Jiang, Youhua;Wang, Wenji;Jiang, Xiangwei;Zhao, Le;Cao, Yilong
    • Journal of Power Electronics
    • /
    • v.19 no.5
    • /
    • pp.1315-1325
    • /
    • 2019
  • Aiming at the negative sequence and harmonic problems in the operation of railway static power conditioners, an optimization compensation strategy for negative sequence and harmonics is studied in this paper. First, the hybrid RPC topology and compensation principle are analyzed to obtain different compensation zone states and current capacities. Second, in order to optimize the RPC capacity configuration, the minimum RPC compensation capacity is calculated according to constraint conditions, and the optimal compensation coefficient and compensation angle are obtained. In addition, the voltage unbalance ${\varepsilon}_U$ and power factor requirements are satisfied. A PSO (Particle Swarm Optimization) algorithm is used to calculate the three indexes for minimum compensating energy. The proposed method can precisely calculate the optimal compensation capacity in real time. Finally, MATLAB simulations and an experimental platform verify the effectiveness and economics of the proposed algorithm.

Condition assessment for high-speed railway bridges based on train-induced strain response

  • Li, Zhonglong;Li, Shunlong;Lv, Jia;Li, Hui
    • Structural Engineering and Mechanics
    • /
    • v.54 no.2
    • /
    • pp.199-219
    • /
    • 2015
  • This paper presents the non-destructive evaluation of a high-speed railway bridge using train-induced strain responses. Based on the train-track-bridge interaction analysis, the strain responses of a high-speed railway bridge under moving trains with different operation status could be calculated. The train induced strain responses could be divided into two parts: the force vibration stage and the free vibration stage. The strain-displacement relationship is analysed and used for deriving critical displacements from theoretical stain measurements at a forced vibration stage. The derived displacements would be suitable for the condition assessment of the bridge through design specifications defined indexes and would show certain limits to the practical application. Thus, the damage identification of high-speed railways, such as the stiffness degradation location, needs to be done by comparing the measured strain response under moving trains in different states because the vehicle types of high-speed railway are relatively clear and definite. The monitored strain responses at the free vibration stage, after trains pass through the bridge, would be used for identifying the strain modes. The relationship between and the degradation degree and the strain mode shapes shows certain rules for the widely used simply supported beam bridges. The numerical simulation proves simple and effective for the proposed method to locate and quantify the stiffness degradation.

Flexural Reliability Assessment of PSC-I Girder Rail Bridge Under Operation (사용중 PSC-I 거더 철도 교량의 휨모멘트에 대한 신뢰도 분석)

  • Kim, Ki Hyun;Yeo, Inho;Sim, Hyoung-Bo
    • Journal of the Korean Society for Railway
    • /
    • v.19 no.2
    • /
    • pp.187-194
    • /
    • 2016
  • It is necessary to determine reliability indexes of existing railway bridges prior to setting up a proper target reliability index that can be used to introduce a reliability based limit state design method to design practice. Reliability is evaluated for a six PSC-I girder railway bridge, which is one of many representative types of double-track railway bridges. The reliability assessment is carried out for an edge girder subjected to bending moment. In the assessment, the flexural resistance and the fixed-load effect were obtained using existing statistical values from previous research on the introduction of limit state design to road bridge design. On the other hand, the live-load effect was determined using statistical values obtained from field measurement for the Joong-ang corridor, on which heavy freight trains are frequently passing. The reliability assessment is performed by AFOSM(Advanced First Order Second Moment method) for the limit state equation, and a sensitivity analysis for the reliability is performed for each factor of the load and resistance effects.