A Study Of Track Line Realignment Method Based On Absolute Coordinates

With the railway traffic’s speed increasing and passenger-line’rapid development, train’s running speed is general improved. For the guarantee of safe operation and passengers comfort, the track alignment of fast line needs to be adjusted to original design location during the process of maintenance and reconstruction, and traditional realignment of existing railway line cannot meet the requirement of practical production. For the defects of the traditional methods, along with the development of computer technology and the popularity of high-precision surveying instruments, based on the absolute coordinates of the existing line realignment method, attention was given and gradually extend.This paper explored and analyzed research data of domestic and foreign, combined with the engineering instance of limit invasion of the Shenyang Metro Line1, took researches on track alignment realignment method on the basis of absolute coordinates, the main research content and results are as follows:(1) Though the analysis of application background and research at home and abroad of coordinate method, good application prospects in rapid rail line maintenance and reconstruction based on the absolute coordinates was expected.(2)Proposed recursive total least squares which has errors in the horizontal and vertical coordinates, compared with traditional recursive total least squares, drew the conclusion that alignment fits better after realignment by recursive total least squares. In addition, applied least square principle to automatic identification and piecewise fitting. The experience showed that it can quickly identity the alignment and with relatively high accuracy.(3)Through line and curve alignment parameters after match, the circular curve ingression was calculated. Given the positive-negative of ingression value, the pattern of planar alignment combination was chosen. At the same time, took the constraints of line difference and specification into consideration, preliminarily realignment of the existing line was realized.(4) Using ObjectARX custom entity function, realignment effect drawing of the existing line was shown on the AutoCAD platform. Database access technology was used to automatically generate the computation table of curve move-value for realignment line, so that a direct reference of alignment effect evaluation was provided.(5)Optimization was taken on the basis of preliminary realignment. Case study showed the deficiency of preliminary realignment, through iteration, the optimal line was generated. Based on the optimal line, radius of circular curve and length of transition curve were verified. Experience showed that realignment line meets the original design line to the greatest extent.