Electronic Track Relay

REDI is used in Signalling Systems (IS), in particular to signal occupied/unoccupied track circuits.

REDI (Cat/Prog 825/407, 825/421) complies with the RFI DTCDNSSSTB SR 21 028 C Italian Railways Specification. It is mechanically and electrically suitable with the previous electromechanical track relay and does not require any modification to the 50 Hz systems and to the 83.3 Hz (phase modulation law – PSK). When REDI switches on, it automatically adapts to the system.

REDI works:

  • With different track circuit types (single rail track circuit, double rail track circuit, 50 Hz, 83.3 Hz PSK).
  • As a control relay in Colour Light LED Signals RS type with combined controls.

It is equipped with a Dip-switch to compensate for the phase displacement between Indoor (Locale) and Outdoor (Campagna) Voltages. The Dip-switch allows for the rephasing of the two signal in inputs, introducing a phase displacement between +180° and -180°, in steps of about 6° on the Outdoor (Campagna) received signal. In this way it covers every phase displacement of the system.


REDI is made with a safety architecture that ensures a SIL4 safety integrity level, according to the Cenelec EN 50129 and EN 50126 regulations.


REDI detects the failure of any insulated joint. The operation of REDI is not affected by traction electrification return-current unbalances.


REDI is equipped with an Arc Fault Circuit Interrupter assembled on each relay output contact. This procedure guarantees high reliability of the contacts and avoids the need of external Arc Fault Circuit Interrupters.


REDI can compensate for the phase displacement between Indoor (Locale) and Outdoor (Campagna) Voltages, without using external capacitors. The rephasing of the two signal inputs procedure is helped by appropriate LEDs, that show the phase displacement and guide to the proper rephasing correction (50 Hz and 83.3 Hz) without using external devices.