Procedure for controlling a guide system of a railway construction machine, associated method and associated guide system

A method for operating a measurement system having a tacheometer mounted on a trolley movable on a railroad track undergoing work, a target mounted on a railroad works machine, a set of data on a theoretical line of the railroad track, and a set of data on positions of noteworthy topographic singularities, the method comprising:

• moving the trolley on the railroad track in a working direction from a starting position to an arrival position in proximity to a topographic singularity of arrival indexed in the set of data on positions of noteworthy topographic singularities;
• immobilizing the trolley relative to the railroad track in the arrival position;
• with the trolley being immobilized at the arrival position, sighting the topographic singularity of arrival using the tacheometer and measuring at least a distance, an azimuth angle and an elevation angle characteristic of a relative positioning of the tacheometer relative to the topographic singularity of arrival;
• with the railroad works machine having been brought into the starting position, sighting the target using the tacheometer and measuring at least a distance, an azimuth angle and an elevation angle characteristic of a relative positioning of the tacheometer relative to the target;
• calculating coordinates of the arrival position of the trolley in a floating reference frame, as a function of the measurements performed in the sighting of the topographic singularity of arrival and in the sighting of the target, of additional data relating to the starting position, and of data on positioning of the topographic singularity of arrival read from the set of data on positions of noteworthy topographic singularities, and of data relating to the theoretical line of the track read from the set of data on the theoretical line of the track, and subsequently storing coordinates of the arrival position of the trolley in the floating reference frame.