Centralized Traffic Control

on railroads, a complex of devices used to monitor and control railroad switch layouts and signals from a central point. The most widely used systems are electrical, controlled by electric relay circuits and electric drives. Such systems may be classified by the methods used to switch tracks, monitor the system’s operation, and supply electric power. Systems with local control and power supply are used chiefly at small railroad stations with up to 12 switches; systems with central control and power supply are used at medium and large-size railroad stations. Centralized traffic control equipment used in conjunction with computers has been developed for use in automated railroad control systems.