The Central Control or Network Operations Center (NOC) system is based on QNX- a real time Unix–like operating system well known for its real-time predictability and high availability. It is used in a variety of safety critical applications. The NOC design uses multiple PC’s running redundant tasks such that any computer can fail and the data is simply routed to another available machine.
From this one platform, Computer Aided Dispatch (CAD) and Traffic Optimization can be conducted. The system supports real-time graphics so maps with moving trains are seen immediately. Alarms are sounded when trains fail to execute the movement authorities or drive past a stop point or exceed the speed limit. All train movements and alarms are stored in a log file to be examined in detail later and to generate reports.
The NOC may also include information from crossings and work forces if they are equipped with simple transceivers so that they are included in the on-line monitoring.
The system makes heavy use of the internet and communicates to all system EVU sites to update them with movement authorities (permission to advance a train) and update speed restrictions and track conditions. As a backup, cellular networks can be used as an alternative or backup communications channel which is useful in areas where EVUs are not employed, but cellular communications is available. (Ie: some dark territories can be accessed via cellular).
The system is highly scalable so it can support small monitoring, control and dispatch systems based on several PC’s to a larger installation composed of hundreds of PC’s. These systems can be designed for a particular railway with a customized interface and communications protocol.