Broken rail detection system and method

• US 6,102,340 A
• Filed: 02/06/1998
• Issued: 08/15/2000
• Est. Priority Date: 02/07/1997
• Status: Expired due to Term

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: Ge-Harris Raliway Electronics LLC
• Inventors: Peek, Ernest, Basta, Wayne
• Primary Examiner(s): Le, Mark T.
• Application Number:
  US09/019,166
• Time in Patent Office: 921 Days
• Field of Search: 246/34 R, 246/40, 246/34 B, 246/41, 246/54, 246/118, 246/120, 246/121, 246/122 R, 246/122 A, 246/220, 246/246, 246/255, 324/713, 324/718
• US Class Current: 246/121
• CPC Class Codes: B61L 23/044 Broken rails

Abstract

This invention relates to a system and method of detecting a broken rail in a railway system. The track sensing circuitry of the present invention applies a voltage source at each end of a block of rails and senses the current flowing through the circuitry. The present invention will detect broken rails continuously in a block, even with a train present (except for a break directly beneath the train). Since the rail is continuously checked, the only restriction imposed on train spacing by this track circuit configuration is that only one train can be present in a block at a time.

Claims

1. In a track circuit comprising two or more electrically isolated rails, a method for detecting breaks in the rails comprising the steps of:

(a) electrically interrupting the first of said rails along its length to form plural blocks;

(b) applying a source of voltage having a first polarity at a first end of one of said blocks;

(c) applying a source of voltage having a second polarity at the other end of said one block;

(d) applying a voltage reference to the second of said rails; and

,

(e) measuring the current in said first rail.

2. The method of claim 1, further comprising the steps of:

(a) comparing said measured current against a predetermined current value; and

,

(b) providing a warning signal when said measured current is less than said predetermined current value.

3. The method of claim 1, further comprising the steps of:

(a) maintaining a historical indication of said measured current;

(b) providing a warning signal when said measured current is less that the historical indication.

4. The method of claim 1, further comprising the step of:

(a) testing the circuit formed in said first rail by disconnecting one of said sources of voltage from said first rail.

5. The method of claim 1, further comprising the steps of:

(a) providing a mobile short circuit between said first and second rails;

(b) moving the mobile short circuit along said first and second rails from the first end of said block to the other end of said block;

(c) determining the location of a break along the rails by the location of the mobile short circuit when a change in the measured current is detected.

15. The method of claim 1 wherein said measuring is performed near both ends of the block.

16. The method of claim 4 further comprising:

(a) measuring the current against predetermined current value; and

,

(b) providing a failure indication if the measured current is not below predetermined current value.

6. A method of determining the presence of a rail vehicle along a track circuit comprising two or more electrically isolated rails, comprising the steps of:

(a) electrically interrupting the first of said rails along its length to form plural blocks;

(b) applying a source of voltage having a first polarity at a first end of one of said blocks;

(c) applying a source of voltage having a second polarity at the other end of said one block;

(d) applying a voltage reference to the second of said rails;

(e) measuring the current in said first rail at said first ends of said block;

(f) removing the source of voltage at the other of said ends of said block; and

,

(g) measuring the current in said first rail at said first end of said block after the source of voltage has been removed at said other end of said block.

7. A circuit for detecting a break in a track circuit comprising two rails, said circuit comprising:

a first rail having electrically isolated blocks along its length;

a second rail forming a substantially continuous electrical path;

a source of voltage of a first polarity electrically connected to a first end of one of said blocks;

a source of voltage of a second polarity electrically connected to the other end of said one of said blocks;

a common reference electrically connected to said second rail; and

,

means for determining the current flowing in said one of said blocks in said first rail.

8. The circuit of claim 7 further comprising means for selectively removing one of said sources of voltage from said first rail.

9. The circuit of claim 8 further comprising means for selectively shorting said rails to each other.

10. The circuit of claim 7 wherein said means for determining comprises means for applying said current across a resistor and means for determining the voltage drop across the resistor.

11. The circuit of claim 8 wherein said means for selectively removing comprises a normally-closed relay.

12. The circuit of claim 7 wherein said means for determining is located near one of said ends of said block.

13. A system for detecting a broken rail within a track circuit comprising plural of the circuits of claim 7, each of said circuits occupying adjacent ones of said blocks.

14. The system of claim 13 wherein the sources of voltage at adjacent ends of adjacent blocks are of opposite polarity.

17. In a track circuit comprising a first set of two electrically isolated rails, a manual throw switch and a second set of electrically isolated rails, said manual throw switch selectively moving a portion of said second set of rails adjacent said first set of rails such that a vehicle travelling along said first set of rails may be selectively switched to travel along said second set of rails, a method of determining whether the manual throw switch is in the normal position wherein a vehicle traveling along said first set of rails continues to travel on first set of rails rather than on said second set of rails, comprising the steps of:

(1) electrically interrupting the first rail of said first set of rails along its length to form plural blocks, one of said blocks including the manual throw switch;

(2) applying a source of voltage having a first polarity at a first end of said one block;

(3) applying a source of voltage having a second polarity at the other end of said one block;

(4) electrically interrupting the first rail at the manual throw switch;

(5) applying a voltage reference to the second of said rails in said first set of rails;

(6) connecting contact across interrupted rail at the manual throw switch when the switch is in the normal position; and

(7) measuring the current in said first rail of said first set of rails at both ends of said block.

18. In a train track circuit comprising two or more electrically isolated train rails and a train traveling in contact with the rails, a method of detecting a break in the rails comprising:

(a) applying a first source of voltage having a first polarity at a first end of the first of said train rails;

(b) applying a second source of voltage having a second polarity at the other end of the first of said train rails;

(c) applying a voltage reference to the second of said rails;

(d) shorting the train rails together to form a first current loop through a first set of wheels and axle on the train and said first source of voltage;

(e) shorting the train rails together to form a second current loop through a second set of wheels and axle on the train and said second source of voltage;

(f) measuring the current in said first and second current loops.

19. The method of claim 18 further comprising determining the location of the train by comparing the measured loop currents with historical values for the loop currents.

20. The method of claim 18 further comprising the step of locating the break in the rails by determining the location of the train when the break is detected.

21. A circuit for detecting a break in a train track circuit comprising two rails while a train is traveling over the rails, said circuit comprising:

a first source of voltage of a first polarity electrically connected to a first end of the first of said rails;

a second source of voltage of a second polarity electrically connected to the other end of the first of said rails;

a common reference electrically connected to the second rail at both ends of said second rail;

a first electrical short between said rails through a first set of wheels and axle of the train forming a first current loop;

a second electrical short between said rails through a second set of wheels and axle of the train forming a second current loop;

means for determining the current flowing in each of said current loops.

22. The circuit of claim 21 further comprising means for determining the location of the train by comparing the measured loop currents with historical values for the loop currents.

23. The circuit of claim 21 further comprising means for determining the location of the brake in the rails by determining the location of the train when the break in the rails is detected.