GROUND-TO-TRAIN TELECOMMUNICATION SYSTEM FOR A. C. ELECTRICAL TRACTION RAILWAYS.

The control and supervision of railroad traffic necessitates and efficient system of communication between running trains and fixed control centers. This problem has been solved in Italy in various ways. One approach calls for using the electric traction line of the railroad as the physical transmission bearer. A first theoretical study of the train-to-ground communication system was made to fix the basic transmission characteristics, and then an engineering plan was developed to allow for the system implementation in the railroads. The experience gathered from field work and from several systems installed have provided further information on the problems related to this type of taransmission. This paper discusses some aspects of the problem and presents results of investigations on the subject.