Telephone and data network for railway - has manual, semi-automatic and automatic operations at different operating levels

摘要

The telephone and data network, for railways, has manual, semi-automatic and automatic operations distributed amongst different operating levels such that each subsystem associated with any operating level is controlled and/or performs a control function in conjunction with subsystems in other operating levls. The components comprising any subsystem are such that the whole system can be expanded to any wanted size using interfaces to interconnect subsystems - which are thereby interchangeable at any operating level. The operating connections may form a branching tree structure.