Patent ID: 7542830

Claim:
A method for processing coordinates of points along an existing track to obtain a desired track alignment defined by a sequence of tangent and circular arc segments and of spirals connecting adjacent segments so that track compass bearing and curvature are continuous throughout whose lateral distances from respective adjacent points on the existing track are minimized, comprising the steps of: accepting instructions from a user specifying a sequence of tangent and circular arc track segments to be incorporated into a desired track alignment and specifying initial estimates for locations of a beginning and of an end of each tangent and arc segment; making initial estimates of positioning of tangents and of positioning and radii of arcs by means such as least squares fitting of a tangent or arc to coordinates of points along the existing track that are between the beginning and the end of the tangent or arc segment; carrying out iterative searching to find a configuration of the tangent and arc segments and connecting spirals so that the tangents, arcs, and spirals taken together are as close as practical to the existing track points based on a measure such as root mean square of transverse distances from adjacent points on the existing track; adopting the said configuration of tangents, arcs, and spirals as the desired alignment for a corresponding section of track; and calculating instructions directing a track lining machine to adjust the track to conform to said configuration.