Autonomous Control Technique for Gradual Systems Expansion

ATOS(Autonomous Decentralized Transportation Operation Control System) is a railway system of primary importance in Tokyo underpinning the city's social infrastructure. The 1st line to use this system began operation in 1996 and today ATOS operates on 22 lines. In recent years, ATOS has required a renewal of its system architecture to adapt to the latest developments in railway operations such as direct operation between lines and improvements to passenger information services. Implementation of a system wide upgrade required gradual change because of the system's huge size, societal dependency, and volume of passengers. What follows is a methodology for changing the communications networks in a huge system effectively, in limited time and without negative influence to the other parts of the system.