The invention relates to a method for operating an automatic train control system (1) having an electronic signal box (2), which has a connected balise (3) and a connected frequency track circuit (10). In order to design such a train control system in such a way that the train control system can be simply constructed from components of the European train control system and of the frequency track circuit without substantial additional development effort, the balise (3) is acted upon by means of indicator messages of a first type (first indicator messages (ZT1)) of the electronic signal box (2) via an actuation module (5) for modular elements having an addressable memory for the number of currently free block route segments, and indicator messages of a third type (third indicator messages (ZT3)) are created from indicator messages of a second type (second indicator messages (ZT2)) of the electronic signal box (2), wherein a functional relationship between the addresses (Add1 to AddX) of the memory and code information (L5 to LU2) of the frequency track circuit (10) are taken into account during the creation of the third indicator messages (ZT3). At least one transmitter (9) of the frequency track circuit (10) is acted upon via a relay assembly (8) as a result of said third indicator messages (ZT3). The invention further relates to an automatic train control system.