Optimization Research On Urban Rail Train Operation Plan Under Different Operating Modes

As a popular means of public transportation,urban rail transit plays a very important role in relieving traffic pressure and optimizing urban layout.In the process of new urbanization oriented by city clusters and metropolitan areas,the mileage of urban rail transit has extended repeatedly and presented operation characteristic trending ultra-long lines and its network.This greatly improves the accessibility and travel service level of residents.However,it also aggravates the difference of passenger distribution and the complexity relationship between supply and demand,leading to the main capacity allocation means to adjust the departure interval is difficult to adapt to the complex passenger flow demand on the ultra-long lines during the urban rail transit operating.Therefore,how to explore the urban rail train operation plan,satisfied with its equipment conditions and passenger demand from the operation model of stop scheme,routing scheme and formation scheme,is great significance to coordinate transport capacity supply,improve transport service quality and enterprise operation benefit.Based on this reason,according to the urban rail transit present operation organization,this paper researches the urban rail train operation plan under different operating model from the perspective of matching passenger flow demand,after the introduction and analysis of existing research.The specific contents include:(1)The characteristic of urban rail passenger flow distribution in time and space is analyzed,and find that clustering effect makes the passenger flow on the same attribute day show strong stability and regularity,but the differential distribution of passenger flow at each section in different periods is the main difficulty to match the demand of passenger flow.Stop scheme,routing scheme and formation scheme,which reflect the diversity of operating mode in urban rail train operation plan,are mainly introduced.The application,the advantage and disadvantage,as well as the present operation,of those schemes are also analyzed.In addition,the key factors in train diagram are also introduced in detail.(2)A passenger flow loading strategy based on direct correlation coefficient(DCC)and Logit model is proposed.The main idea of this strategy is that the arrival passengers in each time period are transformed into waiting passenger for responding train by our introduced DCC,and then,the boarding passengers are confirmed by using Logit model according to the OD demand of waiting passenger and train remain capacity.Based on this,the congestion time that can reflect the persistent effect of passenger congestion state and perceiving differences is specially introduced.After that,the related calculation methods about congestion time,as well as the reference points,are also specifically explained.(3)An optimization model of urban rail train operation plan under single operating mode is constructed,and genetic algorithm and adaptive local solution strategy are also designed.Thereinto,a multi-point random crossover operator based minimum feasible-crossover gene fragment and mutation operator based on feasible-mutate gene are designed in the genetic algorithm.The core idea of the local solution strategy is to find the reasonable departure time that can meet the passenger flow demand by the strategy of the timely alternation between up and down direction,as well as the recursive rolling of time window.The numerical examples show that: 1)The solution quality of local optimal solution strategy is a little short,but it has high timeliness;2)Considering congestion time,about 9.3% of waiting time is sacrificed,but23.9% of congestion time is compressed.(4)With respect to the problem of urban rail train operation plan under skipping overtaking mode,after the consideration of constrains about passenger accessibility and overtaking station position limitation,a mathematical optimization model with strongly universality is established by the introduction of feasible skipping station set,verboten skipping station set,feasible overtaking station set and verboten overtaking station set.An adaptive heuristic solution strategy based on genetic algorithm is also designed according to the proposed model features.Our numerical examples show that: 1)Train overtaking under this mode mainly occurs in the peak passenger flow hours;2)When setting the feasible skipping station,it needs to consider the passenger flow in this station and corresponding section comprehensively.A more reasonable feasible overtaking station should locate in the middle of the line and the station with relatively small passenger flow.(5)With respect to the problem of urban rail train operation plan under multi-routes and multi-groups mode,after the introduction of station set on each route and train formation type set,a mathematical optimization model is established with the consideration of constrains about passenger accessibility and efficient matching between train route and train formation.After that,an adaptive local optimal solution strategy based on scheme combination is designed.Our numerical examples show that: 1)Passenger waiting time and congestion time can be saved by selecting reasonable formation train,and passenger comfort and train capacity utilization can be improved by operating small routing train appropriately;2)On the long route,it is little significance to set turn-back station with short distance for operation small routing train,and utilization of turn-back station is not efficient.