Special edition paper

from voltage control to information control through an optical fiber network, thus achieving a reduction of metallic cables, easy installation and simplification of operation tests. On the other hand, the logical devices to determine the control information of the signal devices still exist separately according to functions such as those for interlocking equipment and the automatic train protection (ATP) controller, and they remain complex. This complex configuration causes complications in designing, installing and maintaining the system, and it decreases the system’s availability. To solve these issues, we have been developing an Integrated Logical Controller (LC), a set of high-performance computers integrating logical devices in a signal house. In this paper, development of the LC and the development policy towards achieving a practical system will be described. Railway service improvements such as expansion of through service over multiple lines and increase of service have been in high demand recently. To meet these customer needs, the signaling system needs to be upgraded. At the same time, much interlocking equipment is about to reach its service life and needs to be replaced within the next several years. However, signaling systems are designed with a focus on high safety and reliability, bringing about complications in installing and upgrading. With a goal of easy installation (i.e. shortening the construction period and improving construction work), the new “IP Network-based Signal Control System ” signaling system that achieves information control of the signal devices in the field and improves flexibility of their upgrading has been developed. By developing this system, field device control was change