集装箱中心站装卸作业线接触网终点设计

在接触网终点设计常规下锚结构形式下,集装箱中心站龙门吊装卸作业线股道接触网终点的有效行车距离无法满足电力机车直接摘挂货物列车要求。本文针对该问题提出了新型的接触网终点下锚结构形式,改进后的下锚结构形式能在不影响龙门吊作业的前提下延长接触网终点有效行车距离,满足电力机车直接摘挂取送货物列车的要求。     

大跨度铁路桥梁梁端伸缩装置对列车走行性影响的研究

梁端伸缩装置是大跨度桥梁的重要组成部分,是容易受损的构件之一,对高速车辆的走行性影响较大。本文针对大跨度铁路桥梁梁端伸缩装置,建立结构动力分析的有限元模型,通过多工况车-桥(线)耦合振动计算,分析梁端伸缩装置自身变形、安装误差及梁端折角等因素对列车走行性的影响,提出车辆平稳性和乘客对车辆振动感觉的评判标准,并进一步基于车辆的平稳性和乘客对车辆振动的感觉确定车速及梁端竖向折角限值。研究表明,车辆响应对梁端竖向折角较为敏感。     

CBTC列车安全定位中通信中断时间的研究

通信中断的存在会对目前城市轨道交通的CBTC列车安全定位产生影响,进而影响列车安全间隔距离。CBTC车地通信系统大多采用无线局域网技术。越区切换中断是导致通信中断的主要原因,根据IEEE 802.11协议的越区切换流程,本文推导出越区切换中断时间与列车速度的关系表达式,在此基础上根据安全定位的实现方法和移动闭塞系统中列车安全间隔距离的计算方法,推导出通信中断时间与影响安全定位的因素之一——估计的运行距离及列车运行安全间隔之间的关系表达式。建立两列列车追踪运行模型,仿真不同通信中断时间下两列车的追踪间隔距离。采用此关系表达式进行理论计算的结果与仿真结果验证了通信中断时间与估计的运行距离及列车运行安全间隔的关系表达式是合理的。     

深圳地铁线网客流分析及与运行图匹配措施研究

深圳地铁二期工程于2011年6月28日投入试运营,形成178 km线网,客运量激增,并具明显特点。通过分析线网客流,尤其是3号线客流特点,制定了工作日早晚高峰及休息日全天的调图措施,以满足服务并买现运能匹配和成本控制。     

跨座式关节型道岔的仿真设计研究

详细介绍重庆跨座式关节型道岔运动系统的仿真设计过程,阐明如何在设计中布置驱动点、计算曲臂长度、布置导槽、获得台车运行轨迹。通过道岔的运动特性分析和道岔的驱动扭矩计算,全面了解道岔的运动特点和各个驱动点的受力状况。     

PLC在沥青混凝土摊铺机行驶控制系统中的应用

结合摊铺机行驶系统的功能要求及PLC的特点，完成了控制系统的硬件设计和软件设计。对其速度闭环控制，引入了PID校正环节，根据控制系统模型动态仿真试验，确定了PID参数。通过PLC模拟试验，初步证实了控制系统设计的可行性和合理性。     

WBZ21型稳定土拌和机行走系统及燃油泵故障的诊断处理

针对WBZ21型稳定土拌和机在施工中其行走系统和燃油泵截流阀所发生的故障问题，提出了一系列故障诊断及排除方法。     

对地铁信号系统列车运行速度制约因素的探讨

信号系统是保障地铁运行安全及提高运行效率的重要设备,列车超速防护功能是信号系统一个非常关键的功能。信号系统防护下的列车运行速度由车辆、线路、轨道、限界及信号系统等条件共同决定。由于相关专业对信号系统安全制动模型不了解,在实际工程中易造成"速度浪费"现象。从信号系统安全制动模型的原理出发,对车辆、线路、轨道、限界等专业对列车运行速度的制约因素进行分析,提出建议。     

Effectiveness of travel time reliability indicators in the light of the assessment of dynamic managed lane strategy

ABSTRACT

The aim of traffic management is to ensure a high quality of service for a maximum number of users by decreasing congestion and increasing safety. Uncertainty of travel times decreases the quality of service and leads end users to modify their plans regardless of the average travel time. Indicators describing travel time reliability are being developed and should be used in the future both for the optimization and for the assessment of active traffic management operations. This article discusses the efficiency of certain reliability indicators in an ex-post assessment of a traffic management strategy. Ex-post assessment is based on an observational before–after study. As some factors other than the studied management strategy may intervene between the two periods, and as most reliability indicators require knowledge of the full travel time distribution and not only its average, a methodology is developed for the identification of the impact of these exogenous factors on the whole distribution. Many reliability indicators are split into different parts allowing the identification of the part due to the management strategy impact. The methodology is tested numerically on a managed lane operation consisting of Hard Shoulder Running (HSR) at rush hour on a section of a French motorway. The variation of some reliability indicators appears misleading, whereas the splitting of the indicators increases our understanding of the strategy and highlights its impact. The paper gives the reliability assessment of the HSR field test and discusses different reliability indicators to identify their potential performances and shortcomings.     

Marine Protected Area Costs as “Beneficial” Fisheries Subsidies: A Global Evaluation

Marine protected areas (MPAs) are now generally accepted as important tools in the protection of coastal biodiversity. It is also likely that they play a positive role in enhancing fisheries. Yet currently, less than 1% of the global oceans are protected, although international agreements have targets ranging from 10–30% coverage. Despite its minuscule size, we consider the current MPA “network” to be beneficial to fisheries, and its running or maintenance cost, therefore, to be a positive contribution to the sustainability of fisheries, or a “beneficial” subsidy (“harmful” subsidies enhance fishing capacity and effort). A method was derived from data in Balmford et al. (PNAS, 101: 9694–9697) to estimate the annual cost of maintaining MPAs as a function of their size, and of the degree of development of the country in question. We provide national costs of the 53 countries that jointly contribute 95% of global fisheries catch and, assuming that this type of subsidy, in a given country, cannot exceed 15% of the ex-vessel value of its fisheries catches, estimated a global MPA subsidy to fisheries of 870 million US$. Given that total subsidies to fisheries currently range from 30–34 billion US$ annually (without MPA costs), this amounts to only 2.5–2.8% of total subsidies to fisheries being devoted explicitly to the maintenance of the biodiversity that sustains them.