About the project

SYTRAL, the urban transport authority in the Lyon metropolitan area, aims to expedite the transition from bus lines powered by internal combustion engines (diesel) to new In Motion Charging (IMC) trolleybus lines by expanding the network. The project builds upon the existing trolleybus network in Lyon, which initially encompassed over 120 km of overhead lines connected to 24 traction substations. The nine pre-existing trolleybus lines were serviced by a fleet of approximately 150 vehicles, some of which were already equipped with IMC technology. This innovation involves charging a traction battery in the vehicle through the overhead line while the vehicle is in motion, enabling autonomous operation even on track sections without overhead lines.

The project entails the development of new overhead line sections and additional substations essential for the seamless functioning of the autonomous trolleybuses. The sizing and design of these new installations were determined through electrical simulations.

Our contribution

Enotrac undertook the task of creating a comprehensive model of Lyon’s 750 V DC trolleybus network as of 2022 (at the project’s inception) using their self-developed software tool, FABEL. Following that, a calibration process was conducted to address the sensitivity and inaccuracies in the input data of the model, with the aim of investigating and minimizing potential disparities between the simulations and real-world conditions. This calibration was performed by employing parameters directly measured on-site, particularly on the vehicles and within the substations

Building upon this foundation, experts conducted numerous studies to assess the feasibility of expanding the infrastructure and/or modifying the network’s operations. These studies were based on predefined scenarios, which encompassed:

  • Infrastructure extensions involving the addition of overhead lines and/or substations.

  • Operational changes encompassing new line routes and alterations in service frequencies.

  • Introduction of new rolling stock.

  • Other isolated or temporary modifications, such as degraded operating conditions, changes in the state of connection between power sectors, or disconnection or removal of sections of the overhead line. These alterations required the examination of new constraints on vehicle autonomy.

By utilizing these extensive simulations and studies, the experts identified appropriate avenues for technical optimization.

overhead lines
first trolleybus in Lyon
  • Client

    SYTRAL Mobilités

  • Period


  • Location

    Lyon, France

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