Operation Tramway 2019 concerns the transformation of the existing Transport on Reserved Track (TVR) line into standard iron trams and its extensions to the Presqu’Île and the Hauts de l’Orne, as well as the creation of a new Tramway Operations and Maintenance Centre (CEMT).The existing line is currently operated with TVR trains and carries around 42,000 passengers per day, equivalent to 50 % of the users of the Twisto network. This existing line, which has malfunctions and users’ disaffection due to its lack of reliability, must be "transformed in order to be operated with a conventional iron tram system.The basic route of the project corresponds to the current route of the TVR line. It will be completed: an extension to Fleury-sur-Orne to eventually serve the future Hauts de l’Orne district and the CEMT; an extension at the level of the Presqu’île; a modification of the route in the area of Campus 2 and Herouville Saint-Clair; a new organisation in the operation of the lines.The operation includes the complete renewal of the tram rolling stock fleet.The Tramways Operating and Maintenance Centre is located on 19 March 1962 Avenue in Fleury-sur-Orne on a land area of 41 741 m for a floor area of 8 017 m. It will include: A maintenance hall with 7 tram lanes, workshops, technical premises and offices. A part operation with the CCP, offices, changing rooms, sanitary facilities and technical premises. A gas station. The development of outdoor spaces on the right-of-way of the plot, including underground networks and retention ponds, roads and car parks, green spaces and fences.An underground cavity independent of adjacent quarries has been identified and required specific treatment. In addition, the site selected is located on an old open-pit quarry and on a polluted right-of-way the scale of which has been revealed during geotechnical surveys carried out during the project phase of the operation. Indeed, the investigations carried out in the field have revealed two major developments: The hold of the former open-pit quarry proved to be wider than originally announced in the first geotechnical surveys conducted in the AVP phase.The mechanical characteristics of the open pit fill are poorer than originally announced.In terms of pollution: Environmental pollution: the surveys reported heterogeneous and potentially polluted fills which could not be completely reused on site or sent to conventional sectors (concrete blocks, household equipment) Sanitary pollution: the polls also reported occasional gas emanations. In the light of this finding, a specific mission to carry out a Quantitative Assessment of Sanitary Risks (EQRS) was commissioned from a specialised study office (Géaupole) to better quantify this risk.The EQRS study concluded that the low concentrations encountered do not pose a risk to CEMT users. These soil hypotheses lead on the one hand, to call into question the foundation system of part of the main building, the service station and the tram tracks passing to the right of that quarry and, on the other hand, to fill the existing quarry and to treat polluted soils.