Patent ID: 7181851

Claim:
A method of tracing a geometry of a track immediately ahead of a ballast pick-up device, with respect to a working direction, and of restoring the geometry after it has been destroyed by an operation of the ballast pick-up device, the method which comprises: moving a first measuring chord along the track, the first measuring chord having a front end point and a rear end point running on the track; measuring a versine of the first measuring chord with a first versine sensor associated with the first measuring chord; storing a measurement value representing the versine in connection with a measurement of a distance travelled, and thereby registering a rear end point of the first measuring chord as a desired position with respect to a local track point; moving a second measuring chord along the track, the second measuring chord following the first measuring chord in the working direction and having a front end point and a rear end point running on the track; and correcting the track geometry by displacing, in a transverse direction of the track, the rear end point of the second measuring chord when the rear end point reaches the local track point, while measuring, with a second versine sensor associated with the second measuring chord, a versine of the second measuring chord until a corresponding measurement value coincides with the stored measurement value, thus indicating that the desired position has been reached.