Cementys monitors the Charles de Gaulle Express
As part of the work on the Charles de Gaulle express (cdgx), Cementys was selected by Eiffage Rail to carry out the inspection of the V2bis and VDIR railway tracks during the earthworks.
Our teams have shown their reactivity to ensure the installation of 2 robotized theodolites and 130 inspection prisms on railroads and shielding heads. This is necessary to ensure the safety of the project and the safety of train users on a daily basis.
In the absence of a power supply, our engineers, in collaboration with our customer, have shown resourcefulness to quickly identify an alternative solution for the operation of the monitoring system, to avoid creating any inconvenience for local residents. For example, high-capacity batteries have been installed underneath the data acquisition units to ensure optimal power supply. The engine-generator was therefore switched on in order to recharge the batteries, which took over at night and on weekends.
The robotic theodolites were installed on the overhead lines, at night under ITC in order to optimize the viewing angles without engaging the train gauge. The installation of the prisms on the rails was done using specially designed rail brackets allowing the non-destructive installation method.
To meet SNCF (NPSF) requirements, each total station was attached to 6 reference points outside the GZI (Geotechnical Zone of Influence) and performed a 20-minute measurement cycle with an accuracy of 1/10th of a millimeter and without interruption. The data recorded in the acquisition station are sent to our server and then published on our secure visualization platform THM Insight, to which the different stakeholders (Eiffage Rail and SNCF) had nominative access.
The objective of this monitoring was to define the movement of the rails in real time during the earthworks by determining the following elements:
The slop is the difference in altitude between the two extremities of a profile on the same track. It is calculated from the values of the Z component of the inspection points.
The track twist is the difference, in absolute terms, between two slops calculated on two consecutive sections. It represents the vertical offset between the two rows of rails.
Longitudinal grading is the vertical distance between the slope of a section over 15 ml of rail and intermediate points spaced every 3 meters.