Dependable integrated surveillance systems for the physical security of metro railways

Rail-based mass transit systems are vulnerable to many criminal acts, ranging from vandalism to terrorism. In this paper, we present the architecture, the main functionalities and the dependability related issues of a security system specifically tailored to metro railways. Heterogeneous intrusion detection, access control, intelligent video-surveillance and sound detection devices are integrated in a cohesive Security Management System (SMS). In case of emergencies, the procedural actions required to the operators involved are orchestrated by the SMS. Redundancy both in sensor dislocation and hardware apparels (e.g. by local or geographical clustering) improve detection reliability, through alarm correlation, and overall system resiliency against both random and malicious threats. Video-analytics is essential, since a small number of operators would be unable to visually control a large number of cameras. Therefore, the visualization of video streams is activated automatically when an alarm is generated by smart-cameras or other sensors, according to an event-driven approach. The system is able to protect stations (accesses, technical rooms, platforms, etc.), tunnels (portals, ventilation shafts, etc.), trains and depots. Presently, the system is being installed in the Metrocampania underground regional railway. To the best of our knowledge, this is the first subway security system featuring artificial intelligence algorithms both for video and audio surveillance. The security system is highly heterogeneous in terms not only of detection technologies but also of embedded computing power and communication facilities. In fact, sensors can differ in their inner hardware-software architecture and thus in the capacity of providing information security and dependability. The focus of this paper is on the development of novel solutions to achieve a measurable level of dependability for the security system in order to fulfill the requirements of the specific application.