Applications of transport economics and imperfect competition

The great majority of analyses made in transport economics use, explicitly or, more often, implicitly, the common assumption of perfect competition. This is the case, for instance, when infrastructure projects are evaluated using the mere sum of the surpluses of transport users and providers. Even when putting aside the question of externalities such as noise, safety or environmental quality, the real chain of economic interactions that takes place in transport provision or downstream of transport provision is not taken into account. Surely enough, describing and simulating this chain could be quite complex. Nevertheless, it is not uninteresting to try to estimate if it does make a big difference or not to make this approximation. The paper makes such an attempt for two broad kinds of applications of transport economics:     

Life cycle assessment of High Speed Rail in China

China has built the world’s largest High Speed Rail (HSR) network. Its environmental impacts have been examined by the means of life cycle assessment (LCA) which describes the whole picture of the HSR system instead of single stages, with a case study for the high-speed railway that links Beijing and Shanghai. The research employs the China-specific life cycle inventory database Chinese Core Life Cycle Database (CLCD). Vehicle operation dominates most impact categories, while vehicle manufacturing/maintenance/disposal and infrastructure construction contribute mostly to mineral consumption (43% and 38%) and organic compounds in water (54% for infrastructure construction). Several scenarios are developed to explore effects of changes in HSR development, utilization, electricity mix, and infrastructure planning and construction. Suggestions are provided for improving the life cycle environmental performance of China’s HSR systems.     

Organizational effects of experience from accidents. Learning in the aftermath of the Tretten and Åsta train accidents

This article explores possible signs on learning in organizations following two major railway accidents in Norway, the Tretten accident in 1975 and the Åsta accident in 2000. These are the most serious railway accidents to have occurred in the past decades and both involved collisions on a single track system. The two events have been analyzed and compared in order to investigate possible learning effects and possible differences in learning given the 25-year span between them. The study is based on the analysis of selected documents related to the accidents in general and the narrative components in the documentation related to learning in particular.Our findings indicate that learning from these events was not expressed as an explicit goal in the aftermath. Learning in these cases seems to be linked for a large part to a change in measures, technical, operational and organizational, but we have not observed any managed confirmation or comprehension processes. The Tretten accident report suggests that the possibility of human error should be mitigated through the implementation of technological barriers, while it omits all other elaborations and risk reducing measures. The Åsta accident report recommended that the work to introduce modern safety management principles that had already been initiated before the accident should be continued. Neither of the accidents yielded any new insights and the knowledge brought forward was merely perceived as confirmation of already-agreed changes.     

Workshop 3A: Governance,contracting, ownership and competition issues in public transport: Looking up not down

Workshop 3A focussed on matters of institutional design that seem likely to improve public transport outcomes. It started by defining high level outcome goals, as measures of ultimate public transport success, and then identified the major societal issues that public transport systems can help to resolve. These issues were separately defined for Southern African and western settings. The importance of taking an integrated approach to transport, particularly land use/transport integration, was seen as fundamental to goal achievement. Workshop papers provided many and varied examples of this importance, ranging from PPPs for major public transport projects to system design issues and contracting out of services. The Workshop included detailed discussion on paratransit development in Southern Africa, where relationship management is proving to be critical, in-line with much previous Thredbo discussion about the important role of trusting partnerships. Parallels and contrasts were drawn with paratransit in western settings. Competition in passenger rail was also a focus, with some questioning of the benefits of franchising. Discussion concluded by proposing recommendations for policy and research and suggesting agenda items for future Thredbo Conferences.     

基于ADAMS的轨距加宽式道岔动力仿真分析

基于动态轨距优化(KGO)的方案,设计了一种18号客运专线轨距加宽式转辙器结构,研究了该结构的初始竖向不平顺。利用美国多体动力学软件ADAMS/Rail建立了客运专线列车CRH1的虚拟样机和道岔模型,对车辆以200 km/h直逆向和80 km/h侧逆向通过道岔轨距加宽式转辙器进行了动力仿真分析。     

轨道交通高架桥桥面综合布置研究

为统一轨道交通桥梁桥面布置,分别研究不同列车型号、受电方式(接触网位置)、疏散方式、消防水管位置、电缆位置情况下的桥面布置,并对比各种布置方式的使用效果,确立较为统一的桥面宽度,推荐标准桥面布置宽度,应用于实际工程,取得了良好的经济和社会效益。     

包钢连铸钢轨落锤断裂原因分析

包钢首批用连铸坯生产的75kg·m-1BNbRE钢轨进行接触焊试验时,出现母材落锤检验不合格。对该批钢轨进行较为全面的性能检验,包括成品钢轨化学成分,氢、氧、氮含量及残留元素复验,拉伸、冲击试验,轨头踏面中心线硬度试验,金相组织、奥氏体晶粒度、非金属夹杂物、低倍组织、脱碳层检验,断裂韧性试验,残余应力测定,落锤试验等。对落锤断裂的原因进行分析讨论。试验结果表明,该批钢轨的材质性能基本合格,成品钢轨轨底残余应力过大是落锤不合格的重要原因之一,而部分炉号钢轨韧塑性能偏低、表面有矫痕等也是影响因素之一。     

A General Method for the Evaluation of Vehicle Manoeuvrability with Special Emphasis on Motorcycles

This paper presents a novel approach to the assessment of the manoeuvrability of vehicles which is not based on the simulation of open-loop manoeuvres, nor does it rely on the modelling of the driver as a control system. Instead, the essence of the method is the solution of a two-point optimal control boundary value problem, in which a vehicle, subject to physical constraints like tyre adherence and road borders, among others, is required to go between given initial and final positions as fast as possible. The control inputs - i.e., the driver's actions - that make the vehicle move between the two states in the most efficient way are found as a part of the solution procedure and represent the actions of a sort of ideal, perfect driver. The resulting motion is called the optimal manoeuvre and, besides being the most efficient way that the given vehicle has for travelling between the two points according to the chosen optimal criterion, may be taken as a reference for meaningful comparisons with other vehicles. The value of the penalty function, used to define the optimal condition occurring at the optimal manoeuvre, may be taken as a measure of manoeuvrability or handling. With this approach the manoeuvrability properties are established as intrinsic to the vehicle, being defined with respect to an ideal perfect driver. Some possible forms of the penalty function, which means slightly different concepts of manoeuvrability and handling, are discussed. In the end, the case of motorcycles and some examples of optimal manoeuvres are given.     

GJ-Ⅲ减振扣件轨道对轨道交通高架段环境噪声的影响分析

为了研究不同形式减振轨道对降低地铁线路高架段环境噪声效果,以国内某地铁高架桥段周边环境噪声为研究对象,分别对列车以110 km/h通过该高架段2种不同轨道时诱发的噪声水平进行测试分析,然后改变原有评价方式,通过引入更符合人耳听觉的响度分析方式对噪声水平进行综合评价,并对比分析两种轨道形式的噪声水平,提出改进思路。结果表明:(1)相比DZⅢ-1型普通减振扣件轨道,GJ-Ⅲ型中等减振扣件轨道除在桥中央线测点处有一定降噪效果外,在其他测点处降噪效果并不明显;(2)通过响度分析发现,GJ-Ⅲ型中等减振扣件可能还会增大人耳对环境噪声的感知情况。