天津地铁2、3号线壁挂DTS机柜电源改造案例分析

基于通信的列车自动控制系统(CBTC)为目前地铁信号系统的主流方向,而随着地铁的普及,信号系统的故障受到越来越多的关注。本文以天津地铁2、3号线信号DTS系统为研究对象,深入分析了该系统在运行过程中发生的电源故障,提出相应的改造方案,通过改造解决该问题,为信号系统维护提供了一定的指导性建议。     

基于弹性概念的城市轨道交通公交桥接问题研究

信号系统是肩负地铁行车安全和效率的安全苛求系统,为了应对信号系统故障难以避免的行车效率波动,提前制定地铁-公交联动应急预案是行之有效的手段之一。文章从轨道交通乘客体验出发,以轨道交通受扰后的恢复能力(即弹性)为优化目标,提出了一种综合考虑路面交通状况、地铁站点地理位置、地铁客流潮汐分布等因素的优化公交桥接应急预案生成方法。首先,在地铁站周边的地图数据的基础上叠加拥堵系数,建立道路拓扑网络模型;而后基于改进的k短路径法计算连接起点和终点地铁站点的最短路径,利用遗传算法优化相关站点所需公交数量,并将该方法应用于地铁5号线。仿真结果表明,通过在故障区域增加临时公交服务,对提升信号系统故障后的城市轨道交通系统弹性具有重要意义,且适当的公交桥接线路的调整更有助于系统弹性的提升。     

地铁故障即信号故障?冤枉!

<正>自百度、谷歌、360搜索等搜索引擎对以"地铁事故"为关键词的搜索结果进行盘点之后发现,在历年地铁事故引发原因的文章中出现最多的字眼即为"信号故障"。经媒体"曝光"过的"地铁信号系统故障"屡见报端,引来不少普通民众质疑,为何"信号故障"成为地铁"大患"并屡治屡犯?对于节奏不断加快的现代城市生活来说,轨道交通在公众的日常生活中占据着举足轻重的地位,因而只要地铁运营发生延误,大家可能就会产生"信号系统又发生故障了"的错觉。     

轨道交通

必维再获无锡地铁信号系统独立安全评估项目近日,必维国际检验集团获得为无锡地铁2号线信号系统提供独立安全评估项目。这是继宁波和武汉地铁项目后,必维在国内的又一个重要的地铁信号系统安全评估项目。据悉,无锡市轨道交通2号线正线全长26.301km,其中高架线6.734km,地下线19.567km。全线共设有车站22座,其中高架站4座,地下站18座,有道岔车站8座,无道岔车站14座。线路共穿越无锡市湖滨区、南长区、崇安区、     

基于振动监测的地铁风机故障诊断研究

针对地铁机电设备检修管理特点,结合地铁风机故障诊断实际需求,以地铁射流风机振动信号为对象,通过振动监测和计算机技术,对风机的轴系故障、轴承故障、电机故障等信号数据特征进行采集,并实现时域特征、频域特征的提取与分析,进而找到能够区分地铁风机故障类型的信号特征,实现地铁机电设备的精准检修,为地铁设备的状态管理提供理论与应用依据。     

浅析轨交ZC系统在故障情况下的应急处置

CBTC系统作为上海轨交10号线整套信号系统的一个核心组成部分,其系统的可靠性和安全性决定了实际运营的高效性。针对CBTC系统中ZC子系统的功能作了介绍,并对ZC系统故障处置进行了分析。结合ZC系统在目前10号线的运用,提出降低故障发生率的建议。     

模糊神经Petri网在管道故障诊断中的应用

针对模糊Petri网在故障诊断中缺乏较强的自学习能力的缺点,将人工神经网络引入到模糊Petri网中,定义一种模糊神经Petri网,应用于天然气长输管道故障诊断,对过程中的故障诊断进行建模,通过分析说明该方法的可行性。     

基于Petri-马尔科夫链的中老铁路通关模式研究

中老铁路作为新开通的跨境运输铁路，为了提高通关效率，研究其通关模式十分重要。分析已有的通关模式，先确定中老铁路口岸站采用“一地两检”的模式，再以货运通关流程为例，构建Petri-马尔科夫链模型，通过建立基本Petri网、随机Petri网以及同构的有穷马尔可夫链，最后求解得到稳定概率及系统的性能参数，根据计算结果验证通关模式的合理性以及发现通关模式中的可优化环节。     

基于Petri网的城市交通应急管理系统分析

交通应急管理系统是交通安全、可靠性运营的保障,是交通发展战略规划中的重要研究内容。为了能对交通应急管理系统进行定量分析,文章从定性的角度分析了影响交通应急管理的因素,建立了城市交通应急管理系统的Petri模型,并利用随机petri网和模糊集理论对建立的模型进行性能分析,同时根据库所繁忙概率和变迁利用率确定影响应急系统性能的薄弱环节,提出提高该交通应急管理系统性能的改善措施。     

地铁民用通信系统资源经营管理模式研究

地铁民用通信系统在满足乘客在地下空间的通信信息需求,为司机、设备维修人员及站务调度等人员提供必要替换通信手段方面,发挥着日益重要的作用。本文通过分析目前我国地铁民用通信系统投资建设、经营管理、维护改造等模式的关键影响因素,对地铁民用通信系统信息平台的统筹经营运作提供了参考借鉴及合理化建议。     

地铁隧道烟气控制模式可行性分析

本文介绍和分析了当前地铁区间隧道烟气控制模式的可行性,指出地铁隧道的火灾探测、确认等基础环节薄弱导致烟气控制模式实现困难;并从与信号制式及地铁运能的角度分析了烟气控制模式对地铁线路运营效率的影响。     

多联式空调机组(VRF)在地铁车站设备管理用房的应用分析

介绍了多联式空调机组(VRF)的发展及应用概况.针对由于地铁车站昼、夜负荷差异而使冷水机组、空调设备夜间频繁开停的问题,探讨了在夜间使用VRF系统的可行性,阐述了使用VRF系统可为城市轨道交通设备管理用房的通风空调系统运营带来的优越性,为相关课题的进一步深入研究探讨提供借鉴和参考.     

System energy optimisation strategies for metros with regeneration

Energy and environmental sustainability in transportation are becoming ever more important. In Europe, the transportation sector is responsible for about 30% of the final end use of energy. Electrified railway systems play an important role in contributing to the reduction of energy usage and CO₂ emissions compared with other transport modes. For metro-transit systems with frequently motoring and braking trains, the effective use of regenerated braking energy is a significant way to reduce the net energy consumption. Although eco-driving strategies have been studied for some time, a comprehensive understanding of how regeneration affects the overall system energy consumption has not been developed. This paper proposes a multi-train traction power network modelling method to determine the system energy flow of the railway system with regenerating braking trains. The initial results show that minimising traction energy use is not the same as minimising the system energy usage in a metro system. An integrated optimisation method is proposed to solve the system energy-saving problem, which takes train movement and electrical power flow into consideration. The results of a study of the Beijing Yizhuang metro line indicate that optimised operation could reduce the energy consumption at the substations by nearly 38.6% compared to that used with the existing ATO operation.     

The impact of metro services on housing prices: a case study from Beijing

Assessment of the impact of metro systems on housing prices is important for financing transport infrastructure via value capture. This paper provides evidence for this relationship, focusing particularly on the effects of metro services, and uses the large city of Beijing, China, as a case study. A spatial error model was applied to 2835 samples of online property sales data obtained in January 2016. Three transport service indicators associated with metro transfers and waiting times were explored: (1) metro headway, (2) access to different metro lines and (3) accessibility to employment opportunities. The results show that areas with more employment opportunities via public transit have higher housing prices than other areas. Shorter metro headways are positively related to housing prices near stations. Housing prices for neighborhoods having access to more than one metro line within 800 m-buffer area are higher than those without access to metro lines, controlling for number of accessible jobs within 30 min. This study sheds light on the importance of metro services on housing prices. It has implications for further research and for the planning policies of metro-dependent cities.

     

An integrated Bayesian approach for passenger flow assignment in metro networks

This paper proposes an integrated Bayesian statistical inference framework to characterize passenger flow assignment model in a complex metro network. In doing so, we combine network cost attribute estimation and passenger route choice modeling using Bayesian inference. We build the posterior density by taking the likelihood of observing passenger travel times provided by smart card data and our prior knowledge about the studied metro network. Given the high-dimensional nature of parameters in this framework, we apply the variable-at-a-time Metropolis sampling algorithm to estimate the mean and Bayesian confidence interval for each parameter in turn. As a numerical example, this integrated approach is applied on the metro network in Singapore. Our result shows that link travel time exhibits a considerable coefficient of variation about 0.17, suggesting that travel time reliability is of high importance to metro operation. The estimation of route choice parameters conforms with previous survey-based studies, showing that the disutility of transfer time is about twice of that of in-vehicle travel time in Singapore metro system.     

Coordination of last train transfers using automated fare collection (AFC) system data

This paper studies last train coordination problem for metro networks, aiming to maximize the total number of passengers who can reach their destinations by metro prior to the end of operation. The concept of last boarding time is defined as the latest time that passengers can board the last trains and reach final destinations. The corresponding method for calculating last boarding time is also put forward. With automatic fare collection system data, an optimization model for coordinating last trains is proposed. The objective function optimizes the number of passengers who can reach their final destinations during the train period using departure times and headways of last trains for each line as decision variables. Afterwards, an adaptive genetic algorithm is put forward to solve this model and is applied to a case study of the Shanghai metro system. Copyright © 2017 John Wiley & Sons, Ltd.     

大跨地铁暗挖车站施工地层变位控制技术研究

在城市中修建地铁暗挖车站,由于开挖跨度大,埋深浅,对地层扰动较大,地表沉降的控制往往成为工程的重点和难点。北京地铁五号线某车站施工时采用数值分析预测、地层变位分部控制,以及信息化施工等措施,成功地将地表沉降控制在设定范围。其研究方法和支护手段,对解决类似大断面暗挖施工具有一定的指导和借鉴意义。     

Developing Metro Systems in the People’s Republic of China: Policy and Gaps

Rapid urbanization has taken place in China since the Open Policy in 1978. In face of the growing demand for mobility in large cities, new metro systems were developed in large cities like Guangzhou and Shanghai. At present, there are seven cities with 10 metro lines under construction. What are the policy issues and major challenges of developing metro systems in China? This paper systematically reviews the current situation and highlights three major gaps that Chinese cities have to overcome in planning metro systems. They are the technology gap, the financing gap and the affordability gap. A discussion of these gaps in the Chinese context leads us to the conclusion that early planning and careful studies are important in the development of metro systems in China. Moreover, the existing official criteria (population and economic power) for approving the building of metro systems are insufficient and should be supplemented by more vigorous evaluation criteria.     

Measuring vulnerability of urban metro network from line operation perspective

Urban metro systems are subject to recurring service disruption for various reasons, such as mechanical or electrical failure, adverse weather, or other accidents. In recent years, studies on metro networks have attracted increasing attention because the consequence of operational accidents is barely affordable. This study proposes to measure the metro network vulnerability from the perspective of line operation by taking the Shanghai metro network as a case study. As opposed to previous studies that focused largely on disruption of important nodes or links, this study investigates the disruption from the line operation perspective. Betweenness centrality (BC) and passenger betweenness centrality (PBC), number of missed trips, weighted average path length, and weighted global efficiency were analyzed considering relative disruption probability of each line. Passenger flow distribution and re-distribution were simulated for different disruption scenarios based on all-or-nothing assignment rule. The results indicate that the metro lines carrying a large number of passengers generally have a significant impact on the network vulnerability. The lines with circular topological form also have a significant influence on passenger flow re-distribution in case of a disruption. The results of this study provide suggestions on metro system administration for potential improvement of the performance of operation, and passengers may meanwhile have an improved alternate plan for their commute trip when a disruption occurs.     

Metro disruption management: Optimal initiation time of substitute bus services under uncertain system recovery time

Determining the initiation time of substitute bus (SB) services is critical for metro disruption management, especially under uncertain recovery time. This study develops a mathematical formulation to determine the optimal initiation time (OIT) of SB services by trading-off their initiation cost and passenger delay cost, thereby minimizing the total system cost. Given the probability distribution of metro disruption duration, we determine the OIT by formulating an optimization problem to minimize the expected total system cost. We then conduct sensitivity analyses of the initiation cost of SB services, passenger value of time, and SB services rate. The results show that SB services ought to be activated only if the metro incident lasts longer than a certain time interval, depending on the factors mentioned earlier, and the OIT should advance with the predicted incident duration. This paper derives analytical results for the case of linear passenger arrival, and determines the results numerically for the case of non-linear passenger arrival when analytical closed-form solutions are not available. The findings will facilitate transit operators to develop response plans in the aftermath of a metro disruption.