Dynamics Study Of Heavy Haul Freight Car Passing The Frog

The frog is an important connection part of the rail switch. The characteristics of it are the complex structure, the easy abrasion and the short service life, which increase the cost of railway operation. With the increase of speed, the effect and the dynamic behavior between wheel and turnout become more and more complex. At the same time, the high speed and the heavy haul railway put forward higher requirements to solve these problems. Low dynamic bogie is an important development direction of high speed and heavy haul freight car at the domestic and foreign. Many experimental and theoretical studies have proved that the low dynamic bogie can reduce the dynamic interaction between wheel and rail, and well solve the contradiction between the hunting stability and curving through performance. However, no study has been done on the effect of low dynamic bogie on the dynamic interaction between wheel and turnout.The profiles of No.12 high manganese steel unmovable frog with 75kg/m rail used in Datong-Qinghuangdao heavy haul railway and the freight car wheel have been measured in this paper. In the survey, it was found that the heart rail worn badly at 240 mm to 480 mm distance away from the theoretical nose of crossing, even peel off block partly. For the analysis of the high manganese steel unmovable frog abrasion, according to the simplified Kalker theory, the vehicle-turnout dynamic model is established. The effects of the freight car through speed, the load condition and the degree of wheel abrasion on the system dynamics performance of the vehicle-turnout and the frog abrasion are analysed. The dynamics performance of the heavy haul freight car is compared with the K6 cross brace bogie, the self steering radial bogie and the forced steering radial bogie, when they pass the crossing area. The research provides a certain theoretical basis for the antifriction measures and the selection of the bogies in the heavy haul railway.When the heavy haul freight car passes the crossing area at different speeds, the rolling circle radius has a larger mutation at the rail with a width of 30 ~ 40 mm, which is about 4 ~ 5mm. At this time, the contact between wheel and frog transits from the wing rail to the heart rail, and the interaction force, the creep rate and the friction power between wheel and turnout fluctuate significantly and reach maximum values. In addition, with the abrasion of the wheel, the position of the maximum value under the standard type surface distance theory tip is about 360 mm, and begins to be delayed, when the wheel abrasion reach a limit, the position of the maximum value to the theory tip is about 560 mm. When the heavy haul freight car passes the standard frog, the friction power reaches the minimum value in the interim of the wheel abrasion. While it passes the worn frog, along with the the wheel abrasion, the friction power has gradually decreased.When the wheel passes from the wing rail to the heart rail, under the condition of the higher speed, radial bogie can effectively reduce the dynamic interaction between wheel and turnout, the abrasion degrees of wheel and frog have a smaller influence on the value of it. The creep rates and the friction power of radial bogie freight car are less than those of the K6 type bogie freight car, which can effectively reduce the creep and the abrasion when the wheel passes from wing rail to the heart rail.