Research On Optimization Algorithm Of Express And Local Line For Urban Rail Transit

ABSTRACT: Chinese authorities have approved38cities to build urban rail transit (URT) by the end of2014; the total mileage of URT will be over6880kilometers. As more and more new lines are put into service in Beijing, Shanghai, Guangzhou and so on, the network operation has taken the place of the single-line operation. At the same time, smaller cities in China also begin the construction of URT. With expansion of urban area, the number of people living in surburbs is gradually increasing. The passenger traffic flow from surburbs to urban area exhibites the characteristics of long travel distance and tides. Express and Local Line is attracting more attention. Skip-stop schedule plan is one of the most important parts of mass transit systems; To do research on optimization algorithm of express and local line for urban rail transit is of profound and important.The paper analyses typical express and local train systems in the world and puts forward the applicability and feasibility of the system. By analyzing its influential factors and constrained factors, the paper builds express and local skip-stop model. As urban rail transport line always has many stations, the general algorithms are often difficult to solve high-dimensional0-1planning problems. Intelligent algorithms can be a good option by imitating evolutionary process which is self-improved with historical progression. By analyzing the advantages and disadvantages of simulated annealing(SA) and Particle Swarm Optimization(PSO) algorithms, the SA-SelPSO algorithm is proposed to solve Express and Local Line problem with integration and improvements of two intelligent algorithms. Then we classify solution methods to deal with the model and validate the feasibility of our methodology by programming in Matlab. At last, the paper analyses relationships between skip-stop plan and influential factors like the proportion of express to local train, driving speed, the main character of passenger flow distribution in different spaces and the system capacity by the study case of Beijing subway line6.Through the case study of Beijing subway line6, the following conclusions are obtained:An express and local line system superior to all-stop needs a reasonable scale of express and local train; The total saving time increases when the number of express train declines; An express and local line system is a more appropriate choice for an unbalance passenger flow distribution; The skip-stop position tends to locate in areas with large passenger flow under strong support; An optimal skip-stop scheme should be with smaller station spacing in the downtown and larger in the suburbs; The express and local system will make system capacity decline, which is suitable for small or medium-sized cities in non-peak times.