Optimizing tram safety and efficiency with preventive maintenance of overhead lines

Context: Preventing the risk of defects in overhead lines

As they move through cities, tramways are powered by a system of electrified overhead lines and a pantograph, which is a device mounted on the roof of an electric train to transmit power from the overhead line to the tram. Over time, the constant tension between these two elements can degrade the overhead lines or the pantograph itself.

The resulting defects can have a negative impact on rolling stock availability, operational safety and maintenance costs. In Lyon, for example, an average of 10 incidents relating to overhead lines and pantographs occur every year, with the most severe cases leading to network disturbances. In October 2020, a pantograph incident caused a half-day outage on two lines, resulting in €30,000 in maintenance costs, 57 lost rides and a major safety risk.

For this reason, preventive maintenance is essential for overhead lines and pantographs on all tramway networks. However, these maintenance operations are made complicated by the fact that they can only be performed by visual inspection on high-tension lines that are located up to 6.5 meters above ground, often in the middle of street traffic.

Innovation: Remote monitoring and IoT data analysis to identify defects

In order to prevent the risks tied to overhead line defects, teams from the Keolis Group and Keolis Lyon are working together on an innovative device to improve the daily maintenance of overhead lines and pantographs. This Proof of Concept (PoC) known as “Pantograph IoT” in Lyon, combines video monitoring, sensors and IoT data analysis located directly on the pantograph to enable a preventive maintenance service for the city’s tramway lines.

In concrete terms, the solution includes an accelerometer mounted on the pantograph, a camera recording every shock on the line, and a 3G box that transmits all data to a centralized platform for analysis. The second step is to sort and select representative data out of the hundred generated every day by one tram: this process can be done thanks to an algorithm which generates a score for every shock recorded. This score is calculated through a formula weighting physical inputs such as the speed of the tram, acceleration of the pantograph... by coefficients adjusted by experience and feedback from operational team. For enhanced preventive maintenance, the system’s IoT Data system ranks them in a list of the Top 20 areas on the network requiring closer inspection.

Meanwhile, Keolis Manchester is testing out an innovative solution for the remote monitoring of the condition of overhead lines on its network. Designed to replace the costly, time-consuming and strenuous work of manually inspecting overhead lines on the network, the new automated system is expected to generate a quick ROI by optimizing maintenance operations.

Value: Enriched preventive maintenance to boost network safety and performance

With this information and IoT Data analysis, teams in Keolis Lyon and Keolis Manchester can improve the efficiency of their preventive maintenance service. By eliminating the risks associated with defects in overhead lines before they cause an incident, the teams are improving both the safety and operational performance of their tramway networks, preventing the life-threatening risks of damaged lines and improving the passenger experience by limiting tram network disturbances.

Following the successful proofs of concept, these projects have demonstrated Keolis’s ability to innovate in terms of maintenance 4.0 while also demonstrating the operational excellence of Keolis teams. Teams will now continue to assess the reliability of these systems, notably in terms of the number of incidents avoided, while also evaluating their potential economic impact.

Next steps: Scaling up and adding useability features

Moving forward, teams at Keolis Lyon plan to work together with the Innovation and Maintenance 4.0 teams to integrate and scale up the solution. At the same time, they will develop new tools to enable staff to use the solution with ease and get access to results fast. These new features will include an advanced dashboard that displays key information to managers, including general trends in terms of defects, incidents and equipment status.

Teams also plan to leverage the system’s IoT data analysis to generate automated alerts, providing real-time information to the Overhead Line team and further improving the preventive maintenance operations. In addition, the next version of the solution will allow teams to finely adjust the settings for each point in the network, so they can collect the exact data they need for their specific inspection operation.

Eventually, the PANTO IOT solution from Keolis Lyon may even combine with the Remote Condition Monitoring solution from Keolis Manchester to form a comprehensive system for optimizing preventive maintenance on overhead lines. Another tremendous example of the international synergies enabled by the Keolis Group!