In the heart of the SNCF station of Marseille Saint Charles and unknown to the general public, the TER Operational Centre is the nerve centre of the TER train traffic. In this veritable control tower, teams supervise 24/7 more than 520 TER trains that run daily in our region, intervene in case of hazards to find resources and solutions to transport passengers to their final destination. But the missions of the TER Operational Centre do not stop there: they also consist in disseminating information to passengers thanks to the various tools visible or viewable by customers: 220 displays in 150 stations, messages on twitter, short-term announcements by controllers, displays at stations, etc. This is all that we propose you to discover during the guided and commented tours of 17 and 18 September, on the occasion of the 2022 European Heritage Days.