Control systems for guided traffic primarily have the task to ensure safe but efficient operation. This paper shows an approach to model such systems in two general steps: The analysis of existing systems to define the functional units and the construction of the train control system. To reach the goal of the train control system specific functions are used which can be classified in functions for protection, supervision of operation and optimization. These functions are modeled as abstract functional blocks, independent from the implementation of a specific train control system. 0-7803-6583-6/00/$10.00 0 2000 IEEE