Study And Application Of Deflection Angle Method And Coordinate Method Based On Existing Railway Lines

During the long term operation of Existing railway,the track geometry is easily degraded due to repetitive train loads,natural disturbance and improper maintenance.Comparing to the straight track,it is especially worse for the curve since the impact,pushing and friction of the curve track are much larger.What’s more,the degradation of the direction of curve track is accelerated.The smaller the curve radius is,the bigger the problem will be.The deteriorated curve will make the rolling of the train,the damage of the train to the track worse,which will leads to a vicious spiral and seriously endangers the safety of the railway system.In order to ensure the safe and smooth operation of the train,maintain the correct and smooth alignment of the curve track,it is essential to adjust the curve in a timely manner.There are many methods for curve alignment,such as rope method,deflection angle method and coordinate method.Comparing to the rope method,deflection method and coordinate measurement method are able to achieve higher precision,so it has been widely used.However,the traditional deflection angle and coordinate method choose a curve closest to the existing curve when calculating and optimizing the curve.In the practice of railway line maintenance,the linear cumulative changes will not only cause the roundness of curve,deviation of straight line,but also lead to double section line spacing inadequate.In calculation of the traditional angle method and coordinate method,a minimum adjustment amount of the curve is used as an optimization target,but for the deviation of straight line and double curve clip section line spacing,the technical standard cannot be satisfied.A case study is carried out,and this paper puts forward the optimization scheme of domestic and foreign surveying and calculation in the process of alignment by means of deflection angle and coordinate method.Taking the alignment of the 7 line reverse curve of the West Marshalling Yard machine as an example,the reverse curve is adjusted by the optimization scheme,so that the straight line of the reverse curve can meet the technical requirements.Take the alignment of Shanghai Kunming railway line at K639,where the line spacing is not enough,as an example,the method proposed in this paper is applied through the optimization scheme and finally technical requirements is satisfied.