SIGNON conducted a study on the electrification of the Brenner Base Tunnel (BBT) back in 2014. Back then, electrification with a 2AC-25-kV-50-Hz system was examined. As part of a new network study to be carried out, the comparative electrification with 15 kV 16.7 Hz, whilst also taking into account an autotransformer system (2AC), was also investigated beyond the national borders.