In the context of the EUREKA CELTIC BOSS project, this paper describes how different mesh networks are used inside commuter trains in order to enhance security of passengers through automatic abnormal event detection and alarm transmission. Several technologies of mesh networks have been considered for indoor train coverage: wireless sensor networks for event detection based on low-power sensors and WiFi-based mesh for video and alerts transmission to the controllers. Coverage studies have been carried out in French commuter trains using these various technologies. Results show that it is efficient to send alarms using a full wireless infrastructure. However, for video transmission new algorithms to increase data rates and fairness are needed. Besides, wireless sensor networks were also integrated in the project final demonstration performed on an operational train.