Railroad Signaling and Communication System Using a Fail-Safe Voltage Sensor to Verify Trackside Conditions in Safety-Critical Railroad Applications

• US 20150191185A1
• Filed: 03/20/2015
• Published: 07/09/2015
• Est. Priority Date: 11/18/2009
• Status: Active Grant

• Current Assignee: Westinghouse Air Brake Technologies Corporation
• Original Assignee: Westinghouse Air Brake Technologies Corporation
• Inventors: PRETORIUS, FRANCOIS, HILL, DAVID L., WISNIEWSKI, CHARLES A., LOWE, LAWRENCE DELOSS III
• Granted Patent: US 9,457,821 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B61L 23/047 Track or rail movements
• CPC Class Codes: B61L 27/53 for trackside elements or systems, e.g. trackside supervision of trackside control system conditions
• CPC Class Codes: B61L 5/06 Electric devices for operating points or scotch-blocks , e.g. using electromotive driving means
• CPC Class Codes: E01B 7/20 Safety means for switches, e.g. switch point protectors, auxiliary or guiding rail members

Abstract

A method and system for verifying trackside conditions in safety critical railroad applications by reporting the status of trackside signals and switches to a remote train control system. The system comprises at least one sensor for providing trackside conditions electrically connected to a circuit for providing trackside conditions to a railroad, said sensor being powered by voltage applied to the circuit such that the sensor is energized only when said electrical component is engaged. The system and method further comprises a method and system which is failsafe and which enables the control system to independently verify signals from each sensor.

Claims

1. A system for verifying whether an electrical component is energized comprising:

a sensor electrically connected to a circuit adjacent to an electrical component, said sensor powered by voltage applied to said circuit such that said sensor is energized only when said electrical component is engaged.

2. The system of claim 1 wherein:

said sensor has a low power microprocessor.

3. The system of claim 2 wherein:

said sensor has a means of two way electronic communication.

4. A railroad signaling and communication method for verifying trackside conditions which are used to control train movement in safety critical railroad applications comprising:

pre-programming at least one sensor for providing trackside conditions to a remote train control system with a unique key and an authentication code generation algorithm;

electrically connecting each sensor to a trackside electrical circuit for providing trackside conditions to a railroad interlocking associated with a trackside signaling electrical component, said circuit including the electrical component and the railroad interlocking, said sensor positioned electrically intermediate to said electrical component and said interlocking;

powering said sensor by voltage applied to said circuit such that said sensor is energized only when said electrical component is engaged;

pre-programming a remote train control system for verifying the status of trackside electrical components indicating track conditions with the unique key assigned to each of the at least one sensors, an identification for the electrical circuit which each of the at least one sensors is connected, and the authentication code generation algorithm;

requesting sensor status by transmitting a challenge message from a remote train control system which is received by energized sensors;

generating an authentication code, in each of the energized sensors, using the unique key for that sensor and authentication code generation algorithm;

creating a response message from each energized sensor containing the authentication code;

transmitting the response message from each energized sensor to the remote train control system;

independently calculating, in the remote train control system, a calculated authentication code for each of the sensors along a particular route using the unique keys, circuit identification, and authentication code generation algorithm pre-programmed into the remote train control system;

validating the response message by matching the calculated authentication codes to the received authentication codes; and

translating the validated response message into a track status message.

5. The railroad signaling and communication method of claim 4 further comprising:

generating a non-repeating number for use with the authentication code generation algorithm;

utilizing both the non-repeating number and the unique key for the sensor as inputs to the authentication code generation algorithm to generate the authentication code for the response message in each energized sensor; and

utilizing both the non-repeating number, the unique key and the circuit identification for each sensor along a particular route as inputs to the authentication code generation algorithm to independently calculate the calculated authentication code in the remote train control system.

6. The railroad signaling and communication method of claim 5 wherein:

the non-repeating number is generated by the remote train control system and transmitted to the energized sensors as part of the challenge message.

7. The railroad signaling and communication method of claim 5 wherein:

the non-repeating number is a time stamp.

8. The railroad signaling and communication method of claim 4 further comprising:

assigning at least two sensors to a master microprocessor creating a cluster of sensors;

transmitting the challenge message from the remote train control system to a master microprocessor;

transmitting the challenge message to each energized sensor by having the master microprocessor sequentially poll each sensor in the cluster;

transmitting the response message from each energized sensor to the master microprocessor;

aggregating the response messages into an aggregate authentication message in the master microprocessor;

transmitting the aggregate authentication message from the master microprocessor to the remote train control system;

validating aggregate authentication message by matching the calculated authentication codes to the authentication codes in the aggregate message; and

translating the validated aggregate authentication message into a track status message.

9. The railroad signaling and communication method of claim 8 further comprising:

generating a non-repeating number for use with the authentication code generation algorithm;

utilizing both the non-repeating number and the unique key for the sensor as inputs to the authentication code generation algorithm to generate the authentication code for the response message in each energized sensor; and

utilizing both the non-repeating number, the unique key and the circuit identification for each sensor in a cluster as inputs to the authentication code generation algorithm to independently calculate the calculated authentication code in the remote train control system.

10. The railroad signaling and communication method of claim 9 further comprising:

generating the non-repeating number in the remote train control system and transmitting the non-repeating number to the master microprocessor as part of the challenge message; and

transmitting the non-repeating number from the master microprocessor to each sensor as part of the challenge message during polling.

11. The railroad signaling and communication method of claim 9 further comprising:

generating the non-repeating number in the master microprocessor and transmitting the non-repeating number to each sensor as part of the challenge message during polling; and

transmitting the non-repeating number from the master microprocessor to the remote train control system as part of the aggregate authentication message.

12. The railroad signaling and communication method of claim 9 wherein:

the non-repeating number is a time stamp.

13. A fail safe method for sensing the status of an electrical component by powering the sensing means with voltage applied to a circuit when the electrical component is engaged comprising:

electrically connecting a sensor to an electrical circuit associated with an electrical component, said circuit energized when said electrical component is engaged, said sensor adjacent to said electrical component;

powering said sensor by voltage applied to said circuit such that said sensor is energized only when said circuit is energized; and

indicating that said electrical component is engaged when sensor is energized by transmitting sensor status to a remote train control system.

14. The method of claim 13 wherein:

said electrical component is a relay;

said circuit is energized when said relay is closed and said sensor is positioned after said relay such that said sensor is energized when said relay is closed.

15. The method of claim 13 wherein:

said electrical component is a switch contact;

said circuit is energized when said switch contact is closed and said sensor is positioned after said switch contact such that said sensor is energized when said switch contact is closed.