Study On Ride Comfort Of The Stiffness Under Track And Dynamic Characteristics Of Turnout

Track rigidity is one of the important parameters in designing railway track, which directly influences the safety and stability of the railway train running. The track rigidity of traditional turnouts in our country is seriously inhomogeneous. With the rapid development of railway and the increase of vehicle operation speed, the inhomogeneous rigidity of turnouts certainly will strengthen the dynamic response of wheel/rail system, influence the stability of vehicles, increase the dynamic stress of track components and shorten their service life. So, the homogenization of track rigidity for turnouts is very necessary in the operation of modern railway.A finite element calculational model of track rigidity for train/frog system has been built according to 60kg /m No. 12 speed-raising single-pointed turnout. The structure characteristics of train/frog system are considered comprehensively in this model including the section changing of point rail, the spacer block, the switch plate, the baseplate pad and the mode of force transformation between the point rail and foundation under rail, etc. By means of the model, the distribution regularity of turnouts has been obtained, on the basis of which, homogenization measure is put forward to further optimize the track rigidity for train/frog system. In addition to the track rigidity calculational model, a dynamic calculational model for the turnout has also been built to discuss the influence on the dynamic characteristics of track structure by changing different kinds of railway parameters.The calculational results show that the track rigidity in the train/frog system is seriously inhomogeneous in both longitudinal and lateral directions. The total rigidity of outer rail changes a little in the longitudinal direction while that of inner rail changes a lot. A sharp increase happens at the (beginning of the point rail and there are three peak values totally. The maximum change rate of total rigidity reaches up to 200%. A homogenization measure has been put forward in this paper through adjusting the rigidity of baseplate pad properly. After the rigidity homogenization with easy realization, the total rigidity in train/frog system has uniform change and the maximum change rate of total rigidity is reduced to 30%. Also, the influence on the track dynamic response is discussed, varying with vehicle speed, axle load, rigidity of fastener, rigidity of baseplate pad and ballast vertical stiffness according to the dynamic evaluation indexes of rail vertical displacement, rail vertical acceleration, sleeper vertical displacement and sleeper vertical acceleration.The analysis results indicate that setting the track rigidity of turnout properly is an efficient method to improve the inhomogeneous rigidity of turnout and guarantee the stability and safety of vehicle. The research on the dynamic characteristics of track structure of turnout will lay a foundation to further study the homogenization of track rigidity for turnout.