Last 31 October 2020, the indexed journal Sensors, rated Q1 in “Instrumentation”, published the article “Automatic Extraction of Power Cables Location in Railways Using Surface LiDAR Systems”. Based on the collaboration between Telice and the Robotics Group of the University of León, a new method that allows one to check the state (height and stagger) of contact and messenger wires in overhead lines was presented.
The assembly and maintenance of electrified railway systems is of vital importance for its correct operation. Contact wires are critical elements since the correct collection of energy from trains through pantographs depends on them. Periodical inspection of the state of these installations is essential. This task traditionally implies a heavy manual workload subject to errors.
The maintenance task is normally performed by workers using manual inspection methods, both direct inspection (in assembly phase, as shown in (a) of figure below) and indirect inspection (with laser rangefinders, as shown in (b) of figure below). These are slow and low productive processes that involve a heavy workload prone to errors (visual readings, take notes on the field, manual data entry in the system, etc.), so its reliability is highly dependent on the operator knowledge and skills.
Inspection trains are the alternative for monitoring overhead contact lines and they include several measurement devices. However, the acquisition of these vehicles implies large purchases and operating costs. They are only functional in long sections (complete line or corridor) and within the framework of maintenance planned by the manager of the infrastructure (often once or twice a year). In addition, the huge amount of data generated makes its management hard.
Therefore, the scope of these systems is limited, making it unsuitable for the daily quality control of a project or as a diagnostic tool for urgent and unexpected problems, fields in which manually operated equipment that makes use of new measurement technologies –like the tCat– are clearly better positioned.
tCat uses LiDAR (Laser imaging Detection And Ranging) technology, which is positioned as one of the most widely used technologies for capturing data in railway environments, since it allows capturing large amounts of data in a short period of time.
tCat can be used both in assembly and maintenance phases, as well as afterwards, allowing the analysis of point clouds previously recorded. The new method proposed in the article was evaluated in both test bench and real environments against the commonly used measurement method. Results with the comparison between this new system and the commonly used measurement method in both test bench and real railway environments were presented, showing differences of less than a centimetre on average.
The result is a significant decrease of time spent for the measuring phase, which is not prone to human errors.