The Berlin S-Bahn Train Control System - Zugbeeinflussungssystem S-Bahn Berlin (ZBS) - is a train protection system based on Eurobalises that is designed for the specific requirements of the S-Bahn Berlin rapid transit rail network. It is able to gradually replace the old system based on train stops with overlap safety.

A Eurobalise is a specific type of a balise installed between the rails of a railway. Eurobalises are part of the European train control system (ETCS). The balises are pre-programmed and contain information that is read by train antennas. One of their many functions is to allow a train to determine its location.