Equipment of Frankfurt’s U-Bahn and S-Bahn with new digital radio systems

Up to now, the Frankfurt am Main Transport Company (VGF) and Deutsche Bahn (DB) have been operating an analog object radio system for the authorities and organizations with security tasks in the tunnels and stations of Frankfurt's rail and metro system, as well as a separate analog radio system for the operation of the metro only.

The goal of the project is to equip the underground transportation facilities of Frankfurt's rail and metro system, as well as the Theater Tunnel – a 415-meter-long two-lane road tunnel – with a new digital radio system. The existing analog operational radio of the VGF will be integrated into the newly constructed antenna system.

In total, 33 underground stations, 36 tunnel sections, 12 tunnel ramps, 5 storage facilities, and approximately 50 emergency exits will be equipped with digital BOS object radio systems.

For this purpose, SISS will provide the active system technology for an optical distribution system (12 Optical Master Units and 118 Repeaters or Optical Remote Units), as well as all system technology cabinets, power supply, and a network management system for the active components of VGF and DB.

Originally, the project was divided into three construction phases. During execution, the original plan was revised for constructional reasons, and the expansion was adapted to the individual route sections. Mainly during school holidays, one of the three sections was closed for several weeks at a time to ensure continuous work. The anticipated completion and final handover are scheduled for the end of 2026.