The study analyses the concept of the structure of the GIS based engineering information subsystem for the trolleybus catenary network in Vilnius, which focusses on the mechanical components of the overhead catenary infrastructure and their integration into a GIS-based information subsystem. The key components of the subsystem are explored, including spatial data collection, mapping, and real-time monitoring. The study ends with recommendations to improve system performance and reliability through advanced data analytics and preventive maintenance for future studies. The findings indicate that the implementation of the GIS-based subsystem significantly enhances the monitoring, maintenance, and management of the catenary infrastructure, and could further lead to improved efficiency and reliability of trolleybus operations.