Analysis Of Operational Reliability Of Modern Trams In The Early Stage Of Operation

Modern trams as a medium volume of pub lic transportation,are to be widely promoted and applied in many cities of China in recent years.According to the analysis of domestic operation,most modern trams are single-line operation,not yet into the network,leading to a lower line and passenger flow distribution fit,lower passenger flow attraction.During operation,the departure interval is longer and stability of the operation is low.Modern trams conflict with the other traffic modes and the security situation is worrying.In the follow-up for a long period of time,modern trams in our country will remain in the early stages of operation.Therefore,this paper studies the operational reliability of modern trams at this stage,to provide guidance to established urban operations management and to provide theoretical basis and decision support for construction and unbuilt line.The paper describes the economic and technical characteristics,function orientation and adaptability of modern trams.The characteristics of this stage are defined from three aspects of line construction,passenger flow and operation.And the operation characteristics are analyzed from four aspects of passenger flow,running speed,line length and operating environment.Based on the survey data,the paper analyzes the characteristics of passenger flow and the characteristics of passenger travel at the initial stage of operation.The definition of modern trams' operation reliability is defined,which is the ability of modern trams to deliver passengers to their destination on time and safely under the existing road traffic,lines and stations.The influence factors of train operation reliability are discussed from the aspects of running time and running safety.Running time reliability factors include internal factors:right-of-way selection,site placement,driver characteristics,vehicle characteristics,train plans,signal control at intersections,and external factors:passenger demand characteristics and traffic characteristics.Running safety reliability factors are analyzed from four aspects:personnel,facilities,environment and management.Based on the analysis of the running process of the train,the composition and characteristics of the running time are expounded.The reliability of the running time is determined from three aspects of the arrival time interval of the station,the running time of the section and the total running time of the line.The time reliability indexes and the common statistical distributions are summarized,and the distribution of the sample time is fitted.The results show that the Gaussian mixture distribution is the best.Based on the principles of classification and selection of indicators,three types of indicators,quasi-point index,volatility index and probability index,which reflect the initial operational characteristics are proposed,and the index system is established from the spatial and temporal aspects.Quasi-point indicators are calculated according to the site of the arrival time interval and the definition of punctuality.A gaussian mixture distribution model is established for the volatility index,and the EM algorithm is used to solve it.For the probabilistic index,the total probability method is used to.construct the model,and the Monte Carlo method is used to solve.The commonly used method of running safety reliability is summarized.The paper constructes a safety and reliability block diagram of modern tram system based on right-link structure from four aspects of personnel,facilities and equipment and environment,and explains each index.The entropy method is used to determine the index weight,and the safety and reliability model of modern trams is established based on multi-dimension connection numbers.The security reliability is divided into five grades,and the interval value of each grade is given in the early stages of operation.Finally,a case of modern tram line in Huai'an of Jiangsu Province is applied.The results show:the quasi-point of each site on the 1st line as a whole is reliable,the length of the line and the departure of the quasi-site impact site.The late peak of the running time of the section fluctuates greatly and the stability is poor,the run-time reliability of the late peak is lower than that of the early peak,and the run-time reliability of the first and last segments is lower than that of the middle segment.The diurnal variation of the total run-time is not very significant,but it has obvious temporal variation,which can be divided into early peak,middle peak,late peak and flat peak.Through the safety and reliability analysis of the operation of the first line,research shows that:the overall situation is better,the security level of 117 days,low-risk level of 40 days,the risk level of 3 days,no high-risk and dangerous situation.