Modeling Communications-Based Train Control system:A case study

CBTC (Communications Based Train Control) system is a complex hybrid railway application with safety critical character. In this paper, a 3-level hierarchy modeling approach was proposed to address the issue of describing train control for the CBTC system development. The system functions were abstracted as top level functional model based on continuous data flow, train behavior was modeled using discrete state machine in the second level, and the control action was described as continuous data flow in the lowest level. Using SCADE, a case study of CBTC subsystem, Zone Controller, was presented to illustrate the approach. The result shows that the approach offers a rigorous description to CBTC system development; it is helpful to improve system quality.