Abstract: A track circuit for railway systems or the like includes a track segment of predetermined length electrically insulated from an adjacent track segment by an electric joint, which includes a conductor and forms two loops arranged in a longitudinal S-shape within the space between the rails. Units are provided that transmit and receive electric signals and that are operatively coupled with the electric joints. The transmitting/receiving units include a unit transmitting and receiving a high-frequency signal to detect a train on the a track segment, and a unit transmitting and receiving a low-frequency signal which provides the carrier encoded with information to be transmitted to a train-based receiving unit. Units are further provided that enable/disable the high-frequency signal transmitting/receiving units, and units that enable/disable the low-frequency signal transmitting/receiving units, which are alternately actuated. The electric joint includes an internal impedance disposed between the two loops.

Abstract: A track circuit for railway systems or the like includes a track segment of predetermined length electrically insulated from an adjacent track segment by an electric joint, which includes a conductor and forms two loops arranged in a longitudinal S-shape within the space between the rails. Units are provided that transmit and receive electric signals and that are operatively coupled with the electric joints. The transmitting/receiving units include a unit transmitting and receiving a high-frequency signal to detect a train on the a track segment, and a unit transmitting and receiving a low-frequency signal which provides the carrier encoded with information to be transmitted to a train-based receiving unit. Units are further provided that enable/disable the high-frequency signal transmitting/receiving units, and units that enable/disable the low-frequency signal transmitting/receiving units, which are alternately actuated. The electric joint includes an internal impedance disposed between the two loops.

Abstract: A track circuit is used in a railway plant or the like, and comprises a track segment which is isolated electrically from the adjacent segments by electrical splices which consist of a conductor connecting the rails in the shape of an "S" laid flat in the direction of the axis of the track. Stationary ground transmission and reception units we provided for each track segment, and on-board mobile reception units we provided on the trains in transit. The data or the information transmitted by the ground units to the on-board units being conveyed through the rails of each isolated track segment when the train is travelling thereon. According to the invention, with each track segment there is associated a compensation network consisting of capacitors connected to the rails of the track segment and suitably spaced apart. Particular embodiments are provided of the electrical splice and of the transmission/reception units.