System and method for determining rail safety limits

• US 20060020375A1
• Filed: 07/26/2004
• Published: 01/26/2006
• Est. Priority Date: 07/26/2004
• Status: Active Grant

• Current Assignee: Salient Systems, Inc. (LB Foster Company A Pennsylvania Corporation)
• Original Assignee: Salient Systems, Inc. (LB Foster Company A Pennsylvania Corporation)
• Inventors: Harrison, Harold
• Granted Patent: US 7,502,670 B2
• Time in Patent Office: Days
• US Class Current: 701/20
• CPC Class Codes: B61L 23/044 Broken rails
• 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: G01M 5/0025 of elongated objects, e.g. pipes, masts, towers or railways G01M5/0058 takes precedence

Abstract

Methods, systems, and apparatus are disclosed for determining rail safety limits. A first example method is disclosed for determining rail safety limits, including identifying a target rail neutral temperature for a portion of continuous welded rail. The method also includes monitoring a longitudinal stress for the portion of continuous welded rail and monitoring an ambient rail temperature for the portion of continuous welded rail. The method further includes determining a present rail neutral temperature based on the longitudinal stress and the ambient rail temperature. According to the example method, the present rail neutral temperature is compared to the target rail neutral temperature to determine whether a failure of the portion of continuous welded rail has occurred, and an alert is reported if the difference between the present rail neutral temperature and the target rail neutral temperature is within a predetermined range. Other methods, apparatus, and systems are disclosed for presenting determining rail safety limits.

Claims

1. A method for determining rail safety limits, comprising:

identifying a target rail neutral temperature for a portion of continuous welded rail;

monitoring a longitudinal stress for the portion of continuous welded rail;

monitoring an ambient rail temperature for the portion of continuous welded rail;

determining a present rail neutral temperature based on the longitudinal stress and the ambient rail temperature;

comparing the present rail neutral temperature to the target rail neutral temperature to determine whether a failure of the portion of continuous welded rail has occurred; and

reporting an alert if the difference between the present rail neutral temperature and the target rail neutral temperature is within a predetermined range.

2. The method of claim 1, wherein the alert represents a likelihood of a catastrophic failure.

3. The method of claim 1, wherein the alert represents a recommendation for maintenance.

4. The method of claim 1, wherein the alert represents a suggested maximum vehicle speed for the portion of the rail.

5. A method for determining rail safety limits, comprising:

monitoring an ambient rail temperature for a portion of continuous welded rail;

monitoring a longitudinal stress for the portion of continuous welded rail;

determining a rail neutral temperature for the portion of continuous welded rail;

determining a yield strength of a ballast supporting the portion of rail;

determining a high temperature buckling threshold associated with the portion of rail, the high temperature buckling threshold being a function of the yield strength, the rail neutral temperature and the longitudinal stress for the portion of the rail;

comparing the ambient rail temperature to the high temperature buckling threshold to determine a temperature difference; and

reporting an alert if the temperature difference is within a predetermined range.

6. The method of claim 5, wherein the alert represents a likelihood of a catastrophic failure.

7. The method of claim 5, wherein the alert represents a recommendation for maintenance.

8. The method of claim 5, wherein the alert represents a suggested maximum vehicle speed for the portion of the rail.

9. The method of claim 5, wherein determining a yield strength includes compensating for ties moving in ballast.

10. The method of claim 5, wherein determining a yield strength includes compensating for rail slippage within fasteners.

11. The method of claim 5, wherein determining a yield strength includes compensating for ballast tamping.

12. A system for monitoring rail portions, comprising:

a plurality of rail portion stress monitoring devices;

a receiver in communication with each of the plurality of rail stress monitoring devices, the receiver operative to receive rail stress data from each of the rail stress monitoring devices, the receiver further operative to transmit the rail stress data to a rail stress processing apparatus;

the rail stress processing apparatus in communication with the receiver, the rail stress processing apparatus operative to evaluate rail stress data and report alerts based on the rail stress data.

13. The system of claim 12, wherein the rail stress processing apparatus is further operative to report a likelihood of a catastrophic failure.

14. The system of claim 12, wherein the rail stress processing apparatus is further operative to report a recommendation for maintenance.

15. The system of claim 12, wherein the rail stress processing apparatus is further operative to report a suggested maximum vehicle speed for one of the plurality of portions of rail.

16. The system of claim 12, wherein the rail stress processing apparatus is further operative to determine a high temperature buckling threshold.

17. The system of claim 16, wherein the rail stress processing apparatus determines a high temperature buckling threshold according to historical mathematical models.

18. The system of claim 12, wherein the rail stress processing apparatus is further operative to determine a yield strength associated with each of the plurality of rail portions.

19. The system of claim 18, wherein the rail stress processing apparatus determines a yield strength associated with each of the plurality of rail portions including compensating for rail slippage within fasteners.

20. The system of claim 18, wherein the rail stress processing apparatus determines a yield strength associated with each of the plurality of rail portions including compensating for ballast tamping.

21. The system of claim 12, wherein the rail stress processing apparatus is operative to determine and report alternate routes to compensate an unsafe rail portion.

22. The system of claim 12, wherein the rail stress processing apparatus is operative to determine and report suggested maximum vehicle speed associated with one of the plurality of rail portions.

23. An apparatus for determining rail safety limits, comprising:

a processor;

a memory connected to the processor storing a program to control operation of the processor;

the processor operative with said program in memory to;

identify a target rail neutral temperature for a portion of continuous welded rail;

monitor a longitudinal stress for the portion of continuous welded rail;

monitor an ambient rail temperature for the portion of continuous welded rail;

determine a present rail neutral temperature based on the longitudinal stress and the ambient rail temperature;

compare the present rail neutral temperature to the target rail neutral temperature to determine whether a failure of the portion of continuous welded rail has occurred; and

report an alert if the difference between the present rail neutral temperature and the target rail neutral temperature is within a predetermined range.

24. A method for determining rail safety limits, comprising:

a processor;

a memory connected to the processor storing a program to control operation of the processor;

the processor operative with said program in memory to;

identify a rail neutral temperature for a portion of rail;

monitor a longitudinal stress for the portion of rail;

determine a yield strength of a ballast (structure) supporting the portion of rail;

determine a high temperature buckling threshold associated with the portion of rail, the high temperature buckling threshold being a function of the yield strength, the rail neutral temperature and the longitudinal stress for the portion of the rail;

compare the rail neutral temperature to the high temperature buckling threshold to determine a temperature difference/gradient; and

report an alert if the temperature difference is within a predetermined range.