Theory And Methods Of Post Evaluation On Railway Construction Project

The post evaluation of railway construction project is differentiated from those of general construction projects in its theory, contents and techniques because of railway’s network infrastructure characteristics and its systematic operation complexity. The study on the basic theory and methods of post evaluation of railway construction project is of great significance in the rational decision-making of project planning and in the improvement of operation, management and service under the circumstances of continuous infrastructure construction, enhanced network quality and improved demand-supply correlation.Considering the existing problems in the research and practice in post evaluation of railway construction project, issues on the post evaluation on project classification, cost-benefit analysis, operation and network influence are discussed based on theories of railway industry, transportation demand and supply, and complex network.The achievements of railway industry characteristics research are summarized and then the judgment method on the commonweal railways based on the calculation of commonweal index is put forward according to the composition analysis on the quantitative spillover effect from commonweal railways. The classifications of railway construction projects are made in terms of public welfare, undertaker of investment and finance, role and function in the network, and the business and technical properties. The differences in contents and methods of post evaluation between the classifications of railway construction projects are analyzed.According to different subjects, railway externality is classified as user externality, network externality, social economic externality, environment externality, etc.. The internal benefit of railway construction project is defined as the supplier benefit, while the external benefit includes user benefit, network benefit, social benefit and environment improvement benefit, and then the social cost-benefit calculation method is put forward. The non-linear integer programming model for newly-built railway network benefit calculation is established especially on the basis of the characteristics of railway construction projects. The dynamic K-shortest path optimum algorithm based on the importance levels of vertexes is designed and applied in an example.Based on the systems analysis in transportation demand and supply theory, the post evaluation framework is constructed in the view of demands including operation evaluation on traffic volume prediction, infrastructure service level, transportation product and service quality, and the traffic organization level. The post evaluation method of traffic volume statistics accuracy stratification is put forward, as well as the measuresdealing with inaccuracy of forecast. The evaluation indexes system and quantification method is established including infrastructure, product and service, and traffic organization, which comprises three levels of operation service quality subject to demand. The example and evaluation result of a high-speed railway operation demonstrates its effectiveness. Reliability, which is the dominant index of operation service evaluation, is mainly influenced by the distribution of redundant time in train diagram. The sectional distributed optimum model for train diagram redundancy is established and calculated by employing the genetic and dynamic programming algorithm. The conclusion from the simulation example of train diagram redundancy for Guangzhou-Shenzhen intercity railway is drawn on the total amount of redundant time, lateral and vertical redundant time distribution, and influences from stopping schedule on redundant time distribution, which can be used as references in enhancingthestability of train diagram.The levels and mechanism of network influence of newly-built railways are analyzed on the basis of the achievements in complex network theory and application. The indexes system of two aspects including network structural performance and social service quality are constructed, comprised of the indexes of the clustering coefficient, the betweenness point, the network efficiency, the connectivity reliability, the network density, the network saturation degree, the traffic volume benefit and the travel time benefit. The post evaluation model based on fuzzy matter-element theory is established. Examples demonstrates that the method and conclusion are in accordance with the characteristics of network composition and with the differences in network influence of different lines and prove to be helpful for decision making in planning.