Electronic track relay, and railroad signaling system using the same

Abstract

In an electronic track relay, electronic relay circuitry receives an input track signal coded at a pre-determined code rate, and regenerates the input track signal at the pre-determined code rate after a predetermined time delay. A driving circuit is coupled to the electronic relay circuitry for receiving the delayed track signal therefrom and conducting, at the predetermined code rate, at least a power source to at least one of various components in a railroad signaling system. A latching circuit is configured for latching the driving circuit into one among a plurality of configurations respectively corresponding to a plurality of different signaling location types, depending on a signaling location type of the railroad signaling system in which the electronic track relay is installed.

1 . An electronic track relay, comprising:
 electronic relay circuitry for receiving an input track signal coded at a pre-determined code rate, and regenerating the input track signal at said pre-determined code rate after a predetermined time delay;   a driving circuit coupled to said electronic relay circuitry for receiving the delayed track signal therefrom and conducting, at the predetermined code rate, at least a power source to at least one of various components in a railroad signaling system; and   a latching circuit for latching the driving circuit into one among a plurality of configurations respectively corresponding to a plurality of different signaling location types, depending on a signaling location type of the railroad signaling system in which the electronic track relay is installed.   
     
     
         2 . The electronic track relay of  claim 1 , wherein said electronic relay circuitry comprises a micro-controller configured for
 automatically determining the signaling location type of the railroad signaling system in which the electronic track relay is installed, and   controlling the latching circuit to latch the driving circuit into the configuration corresponding to the determined signaling location type.   
     
     
         3 . The electronic track relay of  claim 2 , wherein said micro-controller is configured for automatically determining the signaling location type of the railroad signaling system based on a power supply scheme of the railroad signaling system. 
     
     
         4 . The electronic track relay of  claim 2 , wherein said micro-controller is configured for
 periodically checking whether the latching circuit is in a proper position corresponding to the determined signaling location type; and   if the latching circuit is determined to be in an improper position, refreshing the latching circuit to ensure that the latching circuit is in the proper position.   
     
     
         5 . The electronic track relay of  claim 2 , wherein said micro-controller is configured for
 periodically checking whether the latching circuit is in a proper position by sending currents along a predetermined check loop; and   if the check loop is broken which indicates that the latching circuit is in an improper position, refreshing the latching circuit to ensure that the latching circuit is in the proper position.   
     
     
         6 . The electronic track relay of  claim 2 , wherein
 said latching circuit comprises at least one magnetic latching relay having a plurality of coils corresponding to the plurality of configurations of the driving circuit, respectively; and   said micro-controller is configured for energizing one of said coils of the magnetic latching relay to latch the driving circuit into the configuration corresponding to the signaling location type of the railroad signaling system.   
     
     
         7 . The electronic track relay of  claim 2 , wherein said electronic relay circuitry further comprises
 a track trigger relay for receiving the input track signal from a first output of a phase selective unit of the railroad signaling system; and   a phase trigger relay for receiving an input phase signal from a second output of the phase selective unit of the railroad signaling system;   wherein said micro-controller is coupled to the track trigger relay and the phase trigger relay for controlling operations of the electronic track relay based on the input track signal and the input phase signal.   
     
     
         8 . The electronic track relay of  claim 7 , further comprising
 at least an indicator coupled to be driven by the micro-controller;   wherein said micro-controller is configured to generate various alert signals via said indicator in response to at least one of the following determinations:   that the input phase signal has been lost for a predetermined period;   that the input track signal is out of phase with a phase reference voltage;   that the latching circuit is in an improper position not corresponding to the determined signaling location type of the railroad signaling system in which the electronic track relay is installed; or   that the input track signal has been active for a predetermined period.   
     
     
         9 . The electronic track relay of  claim 8 , wherein said micro-controller is configured to generate said various alert signals via said indicator by flashing said indicator at various intensities and rates. 
     
     
         10 . The electronic track relay of  claim 1 , wherein said electronic relay circuitry is configured for compensating for an increase in the duty cycle of the input track signal. 
     
     
         11 . An electronic track relay for conducting at least one of steady DC currents and coded DC currents to various components in a railroad signaling system, the electronic track relay comprising:
 a first controlling relay having an input connectable to a coding or a steady power source of the railroad signaling system to receive therefrom a square wave signal coded at a predetermined code rate and duty cycle or a steady state current, respectively;   a second controlling relay for receiving a phase voltage status signal from the railroad signaling system;   a micro-controller integrated circuit coupled to an output of each of the first and second controlling relays for receiving the square wave signal and the phase voltage status signal, respectively, the micro-controller integrated circuit comprising a micro-controller programmed time delay regulator circuit for delaying the received square wave signal with a predetermined time delay;   an opto-coupler integrated circuit coupled to the time delay regulator circuit of the micro-controller circuit and conducting, at the pre-determined code rate or in a steady state, at least a power source to certain components in the railroad signaling system; and   a dedicated DC power source coupled to at least the micro-controller integrated circuit for providing an isolated DC power source to the micro-controller integrated circuit.   
     
     
         12 . The electronic track relay of  claim 11 , being configured as a Form C, break before make, Single Pole Double Throw (SPDT) type relay and further comprising
 first and second solid-state relays coupled to the opto-coupler integrated circuit and together defining Normally Closed (N.C.) contacts of said SPDT type relay for conducting the at least one power source to the respective components in the railroad signaling system during an off-time period of the square wave signal.   
     
     
         13 . The electronic track relay of  claim 12 , further comprising
 third and fourth solid-state relays coupled to the opto-coupler integrated circuit and together defining Normally Open (N.O.) contacts of said SPDT type relay for conducting the at least one power source to the respective components in the railroad signaling system during an on-time period of the square wave signal.   
     
     
         14 . The electronic track relay of  claim 13 , wherein said micro-controller integrated circuit is configured for, in an at-rest operation, activating the N.C. contacts in a non-coded output state in response to a steady state of the phase voltage status signal. 
     
     
         15 . The electronic track relay of  claim 13 , wherein said micro-controller integrated circuit is configured for, in an at-rest operation, activating only the N.C. contacts in a non-coded output state in response to an interruption of the phase voltage status signal;
 said electronic track relay further comprising at least an indicator coupled to be driven by the micro-controller integrated circuit which is configured to generate an alert signal via said indicator in response to said interruption of the phase voltage status signal.   
     
     
         16 . The electronic track relay of  claim 15 , wherein said micro-controller integrated circuit is configured, in response to a presence of the square wave signal during the interruption of the phase voltage status signal, for
 deactivating the N.C. contacts,   activating the N.O. contacts in a non-coded output state, and   generating said alert signal via said indicator.   
     
     
         17 . The electronic track relay of  claim 16 , wherein said micro-controller integrated circuit is configured, in response to a restoration of the phase voltage status signal, for
 terminating said alert signal at said indicator, and   resuming either a coding or an at-rest operation depending on whether the square wave signal is present or not, respectively.   
     
     
         18 . The electronic track relay of  claim 13 , wherein said micro-controller integrated circuit is configured, in response to a determination that the N.O. contacts have been active longer than a pre-set time period, for
 deactivating the N.O. contacts, and   outputting DC currents from the N.C. contacts.   
     
     
         19 . A railroad signaling system, comprising:
 a phase selective unit for
 converting AC currents of a predetermined code rate transmitted from a section of track rails into a near square wave signal of said predetermined code rate, and outputting the near square wave signal at a first output, 
 comparing the AC currents with a reference voltage, and outputting a phase voltage status signal based on the comparison at a second output, and 
   an electronic magnetic latching relay comprising
 first and second controlling relays coupled to the first and second outputs of the phase selective unit for receiving the near square wave signal and the phase voltage status signal, respectively, 
 a micro-controller coupled to the first and second controlling relays for receiving and outputting the near square wave signal with a predetermined time delay, and for controlling operations of the electronic magnetic latching relay based on the near square wave signal and the phase voltage status signal, 
 a driving circuit coupled to the micro-controller for receiving the delayed near square wave signal and conducting, at the predetermined code rate, at least a power source to at least a further component of the railroad signaling system, and 
 at least one magnetic latching relay coupled between the micro-controller and the driving circuit for latching the driving circuit into one among a plurality of configurations respectively corresponding to a plurality of different signaling location types, depending on a signaling location type of the railroad signaling system. 
   
     
     
         20 . The railroad signaling system of  claim 19 , further comprising:
 a code follower relay coupled to be driven by the driving circuit for outputting the delayed near square wave signal at the predetermined code rate on a subsequent section of the track rails.