We have developed a novel railway signal control system that operates as a distributed system. It consists of a central control unit (called LC) and terminal devices (called FC) that are distributed at the railroad wayside aid operate signal devices. The Internet technologies and optical LAN technologies have been used as communication methods between the LC and the FCs. While handling enormous amount of electric cables may cause human errors, the system is expected to reduce troubles of the current signal system at construction works thanks to the Internet technologies. The FC is a distributed terminal device that has its own processor and placed at the railroad wayside to control the field signal devices. The LC is a centralized computer device that has software arranged by the function of the field devices. An optical network system and multiple communication paths between the LC and the FCs realize durable transmissions. Moreover, the assure performance of controls and transmissions have been investigated, and the autonomous distributed signal control system is also discussed as the next steps of the system