Impact des postes centraux de supervision de trafic ferroviaire sur la sécurité. (Impact of the automatic train supervision systems on safety)

Title : Impact of the automatic train supervision systems on safety Currently, railway tra c supervision systems are not considered as safety critical (basic safety constraints being ensured by other sub-systems). By taking a closer look, we can notice that these systems are able to prove their e ciency in safety management by o ering critical information to the supervisor confronted with a crisis situation in order to help him to take the right decisions that lead to reduce considerably the impact and the severity of an accident. Taking into account these scenarios in the design in order to contribute to enhance the global safety level is therefore mandatory in a context where the concern of economic e ciency of infrastructures lead to increase tra c. Supervision is tightly related to human decisions ; therefore human factor is to be foremost when designing future supervision systems. ¿is work focuses on evaluating the human-machine interactions and their impact on safety. In order to complete this study, we required the participation of specialists from three main areas. Firstly railway engineers for the technical aspects, secondly human factors and organisational specialists, and thirdly dependability experts to summarize and evaluate the impact on safety caused by the interactions of the two previous components. ¿ese three elds have di erent approaches that can sometimes be contradictory and this thesis tries to set links between them for the common objective to reach a greater safety level. ¿e speci c studies on the human factor have been conducted on a platform designed to supervise the railway tra c installed in the UTC o ces. ¿is platform was composed of an automatic train supervision system coupled with a tra c simulator enabling to re-create the working conditions of a an operator. ¿e objective was to obtain information on the general cognitive processes involved in managing a dynamic tra c environment of trains in order to evaluate the supervising system while in use by operators facing three type of situations : nominal, normal, or degraded. ¿e di culty of such study remains the integration of the results from the observation, with the technics of ergonomical cognitive psychology in the safety analysis. An interdisciplinary approach based on a common referential of these three elds has been proposed in order to get a common model for human ressources and dependability experts. ¿is referential was designed in a systemic perspective of the safety studies.