Abstract: A system for simulating a production environment in which a plurality of components are subject to a plurality of different processes to generate an end product. The system comprises a plurality of modules, each module representing one of said processes and a set of data carriers, representing said components. Each module comprises read circuitry for reading data from a data carrier and means for providing an indication representing whether an attempted transaction of the module is valid or invalid. The validity or invalidity of the transaction is based on a predetermined job route which defines a valid predetermined sequence and timing of processes for each component or set of components. Each data carrier carries a unique identification which can be read by the read circuitry and which represents a component or a set of components.