Study On The Performance Of Tramcar Through Four-rhombus Railway Frog On Steep Gradient

The modern tram system has the advantages of less investment,relatively short construction period,environmental protection and energy saving,and good climbing ability,it has obtained vigorous development in our country.In order to accelerate the construction of new urbanization and improve the level and grade of urban development,realize the urban backbone bus orbit and the fast access to the surrounding national railway line,improve the quality of public transport services in the central city,the modern tram demonstration project of the central city cluster is planned in someplace.In order to save money,one of the four-rhombus railway frog was laid on a line with a two-way slope.In our country,it is the first time to design a rhombic cross for the condition of the large slope.To study the safety and comfort of the trams in different directions of the four rhomboids,thus,it provides certain guidance for the design scheme of tram line.The main research work and related conclusions are as follows:In this paper,collecting and organizing the development at home and abroad and introduces the tram and tram dynamics research present situation,summarizes the tramtrack coupling system dynamics research.According to the principle of space geometry,the contact relation between wheel and rail at different position of the four rhombic frog line is calculated.Thus,the horizontal amplitude of the track in different working conditions is obtained,and the triangular hole amplitude formed by a single bogie with the four rhombus frog lines is presented.The model of wheel load reduction analysis is established,including the following conclusions:with the increase of the amplitude of the triangle pit,the linear rule of the left wheel and the rear axle of the bogie front axle is gradually increased,and the wheel load amplitude is basically the same.The wheel load of the front axle and rear axle of the bogie is gradually reduced,and the amplitude of the wheel is basically the same.The longitudinal stiffness and lateral stiffness of primary suspension have little effect on the load and load reduction,while the vertical stiffness and body weight have a great influence on wheel load and load reduction.Using the theory of vehicle-track coupling dynamics,the dynamic model of the complete tram train-four rhomboid cross coupling system was established by using the multi-rigid body dynamics software SIMPACK.The dynamic performance evaluation index was put forward,and the dynamic response of the empty and overloaded trolley bus with different four rhombus lines was analyzed.When tramcar crossing turnout,its safety meets the requirements,and an the basis of this analysis,the safety impact of lateral wind level,vehicle suspension parameters and track irregularity on the crossing of the vehicle is analyzed.Results shows that the lateral wind has adverse effect on the safety when tramcar crossing the turnout,the larger the wind speed,the more obvious the impact.So it is recommended to operate the tram at the wind speed level at level 7 and below when it is empty.Excited by the irregularity of track,the safety of the vehicle when crossing turnout is reduced.Therefore,it should ensure the construction precision of the large slope frog laid in the area.In order to avoid the subgrade uneven settlement under vehicle load,subgrade must be uniform,dense and stable,so as to ensure the security of tramcar when crossing the turnout.