城际铁路区间通过能力计算方法探讨

针对城际铁路客流具有时段性和周期性的特点,以及对运输质量的要求,在对列车运行图进行结构分析描述的基础上,采用最小列车间隔时间法和低速列车扣除系数法相结合的方法,计算城际铁路区间通过能力。其中,分析了各种速度列车情况下的低速列车扣除系数,并对相关参数进行了说明,阐述了非时段性和高峰小时的区间通过能力计算方法。     

铁路双线区间通过能力计算方法的改进

随着铁路大面积提速调图,运输设备不断更新,高速旅客列车及动车组大量上线运行,运输组织方式发生了改变,现行的计算铁路区间通过能力的扣除系数法已不能正确反映能力利用情况.通过对现行计算方法进行分析并加以改进,保留其简单科学、易懂易用的优点,增强科学性、实用性,使之符合实际情况.     

铁路运输能力计算理论方法改进研究

针对当前铁路运输能力计算面临的新问题,综合分析国内外在铁路运输能力计算方法上的优缺点,提出最适合我国路情的扣除系数法亟需改进。通过提出基准列车和连发率等新概念,改进铁路通过能力计算理论方法．分别对双线自动闭塞线路和客运专线进行扣除系数取值和通过能力计算研究,最后以京沪线一段和京沪高铁为例分别印证改进方法的合理性和可靠性。     

双线自动闭塞区段扣除系数法计算铁路通过能力再研究

针对双线自动闭塞客货共线铁路，对扣除系数法计算铁路通过能力展开再研究。以旅客列车单列越行时的扣除系数作为扣除系数的最大值；在不改变旅客列车运行时刻的前提下，于限制区间旅客列车运行线间按规定间隔时间“插满”货物列车，以可“插入”的最大货物列车数计算通过能力后再反算扣除系数，并以此提出扣除系数最小值的计算方法；将扣除系数和通过能力定义为波动值，并给出其范围的计算公式。选取京沪铁路某一繁忙区段作为算例，分别计算扣除系数及通过能力的最大值和最小值，验证了计算方法的可行性。结果表明：该方法可计算扣除系数及通过能力的理论最大值和最小值，是通过能力计算的一个有效途径；在繁忙区段，扣除系数和通过能力的波动范围很大。     

铁路双线自动闭塞区间通过能力计算方法研究

铁路区间通过能力计算方法的研究,对于铁路运输事业的发展有着重要作用。依据直接计算法的思想,结合具体的运行图铺画,建立铁路双线自动闭塞区间通过能力计算模型,并利用该模型求解郑武客运专线新郑州到新许昌段的通过能力,通过实例验证明该模型的有效性。     

包神铁路能力计算与瓶颈识别疏解研究

包神铁路基础设施不断完善,先进生产技术投入运用,已实现经济社会效益阶跃式发展,逐步成为神华煤炭运输通道的核心干线。包神铁路运能和运量矛盾突出,实时能力计算和瓶颈识别疏解亟待研究。采用分析计算法计算包神铁路能力,利用TDCS数据计算各区间通过的列车数量,车站咽喉区道岔、正线及到发线能力利用率等指标,识别和分析能力瓶颈,系统性地提出包神铁路能力瓶颈消解措施,为包神铁路运输能力科学利用和智能决策提供技术支持。     

高速铁路建设对增加既有线货运能力的影响研究

新建客运专线开通后既有线旅客列车减少,可以增加既有线的货物列车通过能力,缓解货物运输压力.通过对传统货物列车通过能力计算方法的分析,结合既有线旅客列车停运实际情况,考虑了旅客列车扣除系数的变化和不同停运旅客列车结构对通过能力的影响.通过确定追踪连发旅客列车数量及其扣除的时间,计算分散铺画的旅客列车数量,提出增加货车通过能力的计算方法,并通过京广线石家庄—郑州下行方向的实例分析进行计算方法的验证.     

基于UIC406的铁路区段通过能力计算方法研究

以扣除系数为基础的铁路区段通过能力计算方法已不适应我国当前铁路运输组织的需要。根据UIC406内容,研究基于压缩运行图冗余时间及在运行图空闲时间加密列车运行线的铁路区段通过能力计算方法。分析运行图压缩和加密方法的实现过程,给出压缩和加密方法下铁路区段通过能力计算公式,根据压缩及加密方法的实现过程和通过能力计算公式编制铁路通过能力计算系统。以我国某条高速铁路某一区段为例,对所确定的铁路区段通过能力计算方法进行适应性分析。结果表明,该铁路区段通过能力计算方法能够在不改变既有运行图结构的条件下对铁路区段通过能力进行计算,计算结果可以为铁路运营管理部门提供多方面的参考。     

双线自动闭塞区段最大量铺画货物列车运行线的研究

为了在客货共线运行图中有效利用旅客列车运行线两侧的空档,尽可能多地铺画货物列车运行线,以提高区段通过能力,在扣除系数表格计算法的基础上,按照附加扣除时间最少的原则,分析了在双线自动闭塞区段单列旅客列车和2列旅客列车两侧货物列车运行线的合理铺画方案。并通过应用实例给出了最大量铺画货物列车运行线的方法。     

胶州铁路物流中心运量预测研究

胶州铁路物流中心是中国国家铁路集团有限公司首批规划建设的全路二级铁路物流中心,项目的实施对落实国家"公转铁"政策具有重要意义。阐述胶州铁路物流中心辐射范围,分析功能定位,通过对重点企业问卷调查,得到重点服务企业现状运量。在此基础上,探讨铁路物流中心运量预测思路及方法,采用Gomberz成长曲线模型和专家意见法对自变量进行延伸预测,并运用弹性系数法,对胶州铁路物流中心近、远期到达运量和发送运量进行预测,预测结果为胶州铁路物流中心设施规模及功能区布局规划提供数据支撑。     

用蚁群算法求解类TSP问题的研究

铁路运输调度问题能否很好解决对于铁路运输公司至关重要,旅行商问题(简称TSP)经常被用来研究运输调度问题。根据某化工集团铁路运输公司的生产实际,提出了“类TSP”问题,但由于“类TSP”和TSP有很大区别,以前求解TSP的优化算法不能直接用于“类TSP”的求解。利用蚁群算法是可以较好解决TSP的一类新型模拟进化算法,适应“类TSP”的要求,并通过“蚁后规则”和变异机制的引入,提出了一种改进的人工蚁群算法。计算机仿真结果表明该算法求解“类TSP”是行之有效的。     

Identifying sources of systematic variation in direct price elasticities from revealed preference studies of inter-city freight demand

Freight demand elasticity studies vary significantly in terms of the demand measure, data type, estimation method, commodity type, etc. This wide variation makes it difficult to compare empirical estimates when the differences may arise in part from the methods and data used. In this paper we conduct a comparative analysis to identify systematic sources of influence on direct price elasticity estimates in the context of freight transport, distinguishing between road, rail, and sea transport, using published direct price elasticities from 12 elasticity-derivative studies from five countries. The study focuses on revealed preference elasticities defined by the freight rate for tonnes and tonne kilometres of inter-city freight movements. Systematic sources that explain differences in direct price elasticities include the demand elasticity measure, mode, commodity class, model estimation form, country, and temporal nature of data (e.g., cross-section). Analysts can utilise the model outputs to adjust the empirical evidence from specific studies to control for differences that impact on the behavioural implications of comparative evidence.     

Airline new route selection using compromise programming - The case of Taiwan-Europe

The decision to launch a new route has a huge effect on the outcomes of airlines in the market. In order to find potential destinations for airlines, this paper utilizes a compromise programming method for selecting direct flight routes. The selection framework comprises two objective functions, with one maximizing total revenue and the other minimizing total cost. A case studying Taiwan-European region destinations is interpreted in the analysis. The results indicate that four potential routes, including Madrid, Milan, Munich and Zurich should be added to the airlines’ service destinations. Therefore, this research suggested that the airport authority could apply incentives scheme to attract carriers to open new routes and add flight frequencies to strengthen its competitiveness.     

A Scottish east coast European ferry service: review of the issues

Peripheral regions and nations within the EU generally enjoy a balanced mix of transport alternatives for access to the Continent's economic centre. Unique among peripheral regions and nations in Northern Europe, Scotland has no direct ferry service to the Continent and relies for access on ferry services from remote seaports, resulting in a greater relative dependence on land transport, particularly road. The evidence presented in this paper suggests that Scotland does not enjoy direct ferry access with the Continent due to any geographic or economic reason, rather the explanation is more to do with technological obsolescence of existing seaport infrastructure coupled with the lack of sufficient Government initiative to help promote direct links. Ultimately, a direct ferry service could help reduce the effects of peripherality and bring about further integration. It would also spread increasing transport demand across modes.     

Understanding air travellers' trade-offs between connecting flights and surface access characteristics

This paper reports on a study which seeks to improve our understanding of how people choose between different kinds of flight at competing airports, and how their choices are affected by access conditions. In particular, using stated choice data collected in Scotland, it investigates whether improving surface access to regional airports that are in relatively close proximity to one another (Glasgow and Edinburgh) leads people to avoid taking indirect flights from their nearest airport in favour of direct flights from an alternative airport. In line with expectations, our estimation results from Cross-Nested Logit models show strong aversion to connecting flights, resulting in a willingness to either pay higher fares for direct flights or accept non-trivial increases in access time. For the latter, even without the potential new direct rail link between the two airports, current access times are such that a scenario where direct flights were only available at the non-home airport, a substantial share of passengers would choose to travel from the alternative airport.     

How do carriers price connecting flights? Evidence from intercontinental flights from Europe

In civil aviation, hub-and-spoke (HS) networks are used by all large carriers. The importance of this system implies that many travelers use connecting flights. Nevertheless, only scarce knowledge is available on price formation of these trips. In this paper, we focus on the fares of connecting intercontinental flights, with one stop and at least one competing direct flight. We develop a simple model of a HS network, with imperfect substitutability between direct and indirect flights and Cournot competition on every route in the network. We test the model empirically, using reported fares for flights from seven European origins, including the five major airports in Europe, to five non-European destinations. We find that the fare of a connecting flight can be expressed as the weighted average of the fare of its direct competitor, the travel times of both flights its costs and the monetary value of the utility attached to the trip. The weight of the direct fare decreases as product diversity increases.     

The implementation of road user charging and the lessons learnt: the case of Valletta,Malta

Whilst the theory on road pricing is well developed there are only a few schemes operating worldwide with others which have failed to be implemented. One scheme which has received relatively little attention is the Controlled Vehicular Access System (CVA) recently implemented in Valletta, Malta. This paper draws on the experience of Valletta with a move from a fixed annual charge (V-licence) for access into the city to a time-based road user charge implemented in May 2007. The aims of this paper are to identify the reasons why a fixed charge was initially introduced; to review the literature related to implementation of road user charging schemes around the world; to compare the V-licence with the CVA and identify the issues relating to the change from one scheme to another. Through the direct involvement of one of the authors in the design and implementation of the road user charge in Valletta, this paper is based on archival data, direct observation and qualitative interviews. This paper concludes on what lessons can be learnt from the case of Valletta for other cities contemplating the introduction of a road user charge.     

A historic move - the opening of direct flights between Taiwan and China

Political rivals for six decades, Taiwan and China, began regular non-stop passenger flights on July 4, 2008. This paper aims to clarify the implications of the Cross-Strait Air Transport Agreement reached by both countries. It offers a review of air transport development in Taiwan and China and compares their approaches with other countries. In particular, this paper discusses Taiwanese and Chinese perspectives on the opening of direct flights. It goes onto analyse the probable effects of the direct flights and identifies the likely winners and losers. It concludes that strengthening air links between the two countries did reduce travel time considerably for passengers and the resulting growth in business will help cushion the effects of the industry’s current economic downturn.     

Product, operation, and demand relationships between manufacturers and retailers

This paper presents a framework for identifying the most adequate distribution structure between manufacturing and retailers, considering different characteristics of product, operation, and demand. Based on the random generation of different scenarios, it is indicated the adequacy of direct, echeloned, and mixed distribution structures to a given set of demand uncertainty, lead time variability, holding costs, and transportation costs. Sensitivity analyses are also performed to address managerial issues, such as the mission of a Local DC and the convenience of lead time demand pooling. Findings suggest an increase of mixed distribution structures to the detriment of purely direct/echeloned ones.