A scenario-based safety argumentation for CBTC safety case architecture

Abstract

This paper on a scenario-based safety argument for Communication-Based Train Control System (CBTC) safety case architecture is from the proceedings of the 12th International Conference on Computer System Design and Operation in Railways and Other Transit Systems, held in Beijing, China, in 2010. The authors contend that the CBTC system is a symbol that China has stepped onto the stage of rapid urban rail traffic development. They define the CBTC as a safety-critical system that guarantees rail traffic safe-operating and high transportation efficiency. The authors present a promising method based on Goal Structuring Notation (GSN) to establish a composition of safety argumentations for managing safety cases. The method introduces the concept of safety argument modules to express rationally encapsulated goal-based safety claim sets that conform to safety requirements, but are deduced in accordance with hazard analysis based on the operational scenarios. They present an illustrative example of a generic modular safety case architecture for CBTC generic products, to show how the whole safety case architecture is structured to be in line with system requirements. In addition, the example demonstrates the ease with which modules can be updated and reused to conform to revisions in system development.