Research On Optimization Of Rolling Stock For Urban Rail Transit Under Network Operation

Train stocks scheduling is the core part of urban rail transit transportation organization plan and an important research content under network operation.There is a close relationship between transportation efficiency and reasonable usage of train stocks.So that the reasonable train stocks scheduling has important practical significance to improve the operation efficiency and reduce operation expenses.This paper gives the definition of urban rail transit network operation which is based on the background,the attribute and the implement method.On that basis,this paper expounds the characteristics of network operation in practical application,and introduces the transportation organization pattern under network operation and their application cases in home and abroad.According to the characteristics of urban rail transit train stocks and the similarity of that with the multiple traveling salesman problem,the network of train stocks scheduling has been built.Based on analyzing the internal mechanism of train stocks optimization objective,induce the constraint conditions and the objective requirements of train stocks scheduling of urban rail transit.As well as considering the uniqueness constraint,the train stocks connecting time constraint,the departure/return vehicle depot constraint,the capacity of vehicle depot constraint and the cross line ratio constraint,taking the enterprise operation cost and the proportionality of train stock scheduling as objective function,an optimization model for urban rail transit train stock is established based on MTSP.In actual operation,there are some stochastic disturbance factors in the urban rail transit system.That influence on transportation organization is mainly manifested by train running delay.Based on expounding the types of running delay and the distribution of delay time and the characteristics of propagation,the effect of train running delay on train stocks scheduling has been analyzed.In order to improve the anti-interference capability of train stocks scheduling,the system reliability theory has been used to improve train stocks scheduling.The usage of train stocks of urban rail transit is a kind of large-scale combinatorial optimization problem,that is also a kind of NP-hard problem.According to the characteristics of optimization model,and the model solved by using the max-min ant algorithm.Taking a small-size network which composed by line 1,line 2 and line 3 in LZ city as an example,acase study has been carried out to verify the validity and applicability of the model.The results show that the above mentioned model is reasonable and valid,and the train stocks optimization with time delay can increase the robustness of train stocks scheduling.The research content and research method in this paper has certain reference value and method support for urban rail transit usage of train stocks under network operation.