The research work, subject of the present paper, takes place in the framework of line 1 automation project. It is a project that consists of upgrading line 1 (with drivers on-board) to unattended train operation (no drivers or agents on-board) without service interruption. It results a mixed fleet operation for a period of two years between manually driven trains and driverless ones. In this context, the current research work has consisted of developing a model allowing to study and analyse the mixed fleet operation on line 1. Once operational, the model has served to simulate two case studies concerning the management of the mixed trains fleet running inside the terminal stations. They take into account two fundamental constraints: people-staff safety on one hand and quality of service offered to passengers on the other hand. The analysis and the results of these two case studies are described in the present paper