Systems Engineering Framework for Railway Control & Safety Systems

Traditional railway signalling and control systems have been based on fixed block train separation and lineside signals to control the movement of trains and to avoid collisions. This has historically led to a segregation of the functionalities of sub-systems such as signalling, rolling stock and control centres, with the development and delivery of each subsystem being developed and delivered with a very narrow, sequential and design-based approach that relies on a very sequential approach based on previous designs and technology.. Recent developments, such as ERTMS and CBTC, have resulted in more complex systems with greater sub-system interactions, since movement authorities are transmitted over a wireless communications channel between the lineside protection system and the train. This has led to a requirement for a more systems engineering based approach to the development and deployment of these more integrated systems. The author of this paper proposes a systematic approach to railway and train control system development based on a simple functional model that can be applied to all types of such systems.