Length optimization of straight line connecting turnout on main line in high-speed railway station yard

Taking the development of high-speed railway in China as background, and referring to the dynamic theory and wheel-rail contact mode, dynamic analysis model was established, considering the setting position of straight lines and running conditions of train in high-speed railway station yard. Using the established model, and choosing vehicle lateral acceleration and wheel suspension as the evaluation indexes, dynamic characteristic of vehicle traveling in turnout and adjacent area on main line was analyzed, and effects on travelling safety and stability of train aroused by length variation of straight lines were calculated based on analyzing the damping rules of vibration. The results show that, a certain length of straight lines can alleviate the vibration aroused in turnout and curve(turnout), length of straight lines connecting turnouts in different sections on main line was proposed to meet the demand of traveling stability, and shortening or cancelation of straight line for the scale limitation of station yard has less influence on operation safety of train.

A two-layer optimization model for high-speed railway line planning

Line planning is the first important strategic element in the railway operation planning process,which will directly affect the successive planning to determine the efficiency of the whole railway system.A two-layer optimization model is proposed within a simulation framework to deal with the high-speed railway (HSR) line planning problem.In the model,the top layer aims at achieving an optimal stop-schedule set with the service frequencies,and is formulated as a nonlinear program,solved by genetic algorithm.The objective of top layer is tominimize the total operation cost and unserved passenger volume.Given a specific stop-schedule,the bottom layer focuses on weighted passenger flow assignment,formulated as a mixed integer program with the objective of maximizing the served passenger volume andminimizing the total travel time for all passengers.The case study on Taiwan HSR shows that the proposed two-layer model is better than the existing techniques.In addition,this model is also illustrated with the Beijing-Shanghai HSR in China.The result shows that the two-layer optimization model can reduce computation complexity and that an optimal set of stop-schedules can always be generated with less calculation time.

New Monitoring Technologies for Overhead Contact Line at 400 km.h-1

Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line （OCL） components at 400 km.h-1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed mea- surement system is capable of effectively measuring OCL parameters.

Analysis on the influencing factors of mechanical characteristics of jointless turnout group in ballasted track of high-speed railway

Turnouts are in close proximity to each other in the stations of high-speed railway.The stress and deformation of those turnouts which are laid nearby are influenced mutually and therefore those turnouts should be considered together.On the basis of finite element method,according to No.18 jointless turnout with swing nose frog in the ballasted track of high-speed railway,a finite element calculating model of jointless turnout group coupling the longitudinal,lateral and vertical directions is established.The influencing factors,for instance the number of turnouts,connection form,length of intermediate straight line and ballast bed longitudinal resistance,on the mechanical characteristics of turnout,transverse deformation of switch rail and range of rail temperature for laying turnout are analyzed in this paper.The results show that more turnouts result in more obvious interaction between them when the lengths of intermediate straight line are the same;more significant influence between the turnouts with the connection form of head-to-head is produced compared to that of head-to-end;from the perspective of statics,influence between turnouts could be ignored basically if the intermediate straight line is over 50 m;bigger longitudinal resistance of ballast bed leads to less influence between the turnouts.