Unlike the traditional fixed block systems, in the modern moving block CBTC systems the protected section for each train is not statically defined by the infrastructure (except for the virtual block technology, with operating appearance of a moving block but still constrained by physical blocks). Since every block is fixed by the infrastructure, these systems are referred to as fixed block systems. Each block is protected by signals that prevent a train entering an occupied block. Traditional legacy signalling systems are historically based in the detection of the trains in discrete sections of the track called ‘blocks’. The main objective of CBTC is to increase capacity by safely reducing the time interval (headway) between trains travelling along the line.
As a result of this operators are now focused on maximising train line capacity. Metros (and other railway systems) are able to improve headways while maintaining or even improving safety.Ī CBTC system is a “continuous, automatic train control system utilizing high-resolution train location determination, independent of track circuits continuous, high-capacity, bidirectional train-to-wayside data communications and trainborne and wayside processors capable of implementing Automatic Train Protection (ATP) functions, as well as optional Automatic Train Operation (ATO) and Automatic Train Supervision (ATS) functions.”, as defined in theIEEE 1474 standard.Ĭity and population growth increases the need for mass transit transport and signalling systems need to evolve and adapt to safely meet this increase in demand and traffic capacity. This results in a more efficient and safe way to manage the railway traffic. By means of the CBTC systems, the exact position of a train is known more accurately than with the traditional signaling systems.
Communications-Based Train Control (CBTC)Ĭommunications-Based Train Control (CBTC) is a railway signaling system that makes use of the telecommunications between the train and track equipment for the traffic management and infrastructure control.