System and method for predicting future rail temperature

• US 20070265780A1
• Filed: 04/20/2007
• Published: 11/15/2007
• Est. Priority Date: 04/21/2006
• Status: Abandoned Application

• Current Assignee: ENSCO, Incorporated (Teris LLC)
• Original Assignee: ENSCO, Incorporated (Teris LLC)
• Inventors: Zhang, Yu-Jiang, Kesler, Kevin
• Application Number:
  US11/785,923
• Publication Number:
  US 20070265780A1
• Time in Patent Office: Days
• US Class Current: 702/3
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature
• CPC Class Codes: G01W 1/00 Meteorology

Abstract

A system and method for predicting future rail temperature for a rail of a railroad track, the system including a weather data source that provides current and forecasted meteorological data, a database that retrievably stores the meteorological data from the weather data source, and a processor that processes the meteorological data to calculate and output a future rail temperature for a future time based on the meteorological data, accounting for heat transfer characteristics of the rail. In one embodiment, the processor may be implemented to calculate the future rail temperature by determining a rate of change in rail temperature over time, and integrating the rate of change in rail temperature over time.

Claims

1. A system for predicting future rail temperature for a rail of a railroad track, the system comprising:

at least one weather data source that provides current and forecasted meteorological data;

a database that retrievably stores the meteorological data from the at least one weather data source; and

a processor that processes the meteorological data to calculate and output a future rail temperature for a future time based on the meteorological data, accounting for heat transfer characteristics of the rail.

2. The system of claim 1, wherein processor calculates the future rail temperature by determining a rate of change in rail temperature over time, and integrating the rate of change in rail temperature over time.

3. The system of claim 1, further including a warning module adapted to generate a warning signal based on the calculated future rail temperature that is indicative of likelihood of the rail buckling at a future time.

4. The system of claim 1, wherein the at least one weather data source periodically updates the meteorological data, and the processor is further adapted to update the calculated future rail temperature based on the updated meteorological data.

5. The system of claim 1, wherein the heat transfer characteristics of the rail includes at least one of solar absorptivity of the rail, emissivity of the rail, specific heat of the rail, area of rail surface, and volume the rail.

6. The system of claim 1, wherein the processor calculates the future rail temperature further based on an energy equilibrium model for the rail.

7. The system of claim 6, wherein the processor calculates the future rail temperature by determining a rate of change in rail temperature over time in the energy equilibrium model, and integrating the rate of change in rail temperature over time.

8. The system of claim 7, wherein the energy equilibrium model for the rail is represented by equation:

$k<br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\alpha <br><br>}}_s<br><br>A_s<br><br>G_s<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\theta <br><br>}-\left(h_{\mathrm{conv}}<br><br>A_c<br><br>\left(T_r-T_{\mathrm{\infty <br><br>}}\right)+\mathrm{\varepsilon <br><br>\sigma <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>A_r<br><br>\left(T_r^4-T_{\mathrm{sky}}^4\right)+{\stackrel{.}{E}}_{\mathrm{other}}\right)=\mathrm{\rho <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{cV}<br><br>\frac{d<br><br>T_r}{d<br><br>t}$

where;

k—

atmospheric filtering factor;

α

_s—

solar absorptivity of rail;

A_s—

area of rail surface exposed to the sun;

G_s—

solar constant;

θ

—

solar angle;

h_conv—

convection coefficient;

A_c—

area of rail surface subject to convection heat transfer;

T_r—

rail temperature;

T_∞

—

ambient air temperature;

ε

—

emissivity of rail;

σ

—

Stefan-Boltzmann constant;

A_r—

area of rail surface subject to radiation heat transfer;

T_sky—

atmospheric sky temperature above the cloud level;

{dot over (E)}_other—

a term to count for the heat exchange at interfaces of rail-tie and rail-ballast interfaces;

ρ

—

density of rail;

c—

specific heat of rail; and

V—

volume of rail.

9. The system of claim 1, further including at least one temperature sensor that measures the actual temperature of the rail at an instance in time.

10. The system of claim 9, wherein the processor is further adapted to update the predicted future rail temperature using the actual temperature measured.

11. The system of claim 1, wherein the processor is further adapted to process the meteorological data to estimate current rail temperature for use in calculation of the future rail temperature.

12. The system of claim 1, further including a weather station that verifies accuracy of the forecasts of the at least one weather data source.

13. A method for predicting future rail temperature for a rail of a railroad track comprising:

receiving current meteorological data;

receiving forecasted meteorological data; and

processing the received current and forecasted meteorological data to calculate a future rail temperature for a future time, accounting for heat transfer characteristics of the rail.

14. The method of claim 13, wherein calculating the future rail temperature includes determining a rate of change in rail temperature over time, and integrating the rate of change in rail temperature over time.

15. The method of claim 13, further including generating a warning based on the calculated future rail temperature to indicate the likelihood of the rail buckling at a future time.

16. The method of claim 13, further including periodically receiving updated forecasted meteorological data, and updating the calculated future rail temperature based on the updated forecasted meteorological data.

17. The method of claim 13, wherein the heat transfer characteristics of the rail includes at least one of solar absorptivity of the rail, emissivity of the rail, specific heat of the rail, area of rail surface, and volume the rail.

18. The method of claim 13, wherein calculation of the future rail temperature is attained using an energy equilibrium model for the rail.

19. The method of claim 18, wherein calculation of the future rail temperature includes determining a rate of change in rail temperature over time in the energy equilibrium model, and integrating the rate of change in rail temperature over time.

20. The method of claim 17, wherein the energy equilibrium model for the rail is represented by equation:

$k<br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\alpha <br><br>}}_s<br><br>A_s<br><br>G_s<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\theta <br><br>}-\left(h_{\mathrm{conv}}<br><br>A_c<br><br>\left(T_r-T_{\mathrm{\infty <br><br>}}\right)+\mathrm{\varepsilon <br><br>\sigma <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>A_r<br><br>\left(T_r^4-T_{\mathrm{sky}}^4\right)+{\stackrel{.}{E}}_{\mathrm{other}}\right)=\mathrm{\rho <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{cV}<br><br>\frac{d<br><br>T_r}{d<br><br>t}$

where;

k—

atmospheric filtering factor;

α

_s—

solar absorptivity of rail;

A_s—

area of rail surface exposed to the sun;

G_s—

solar constant;

θ

—

solar angle;

h_conv—

convection coefficient;

A_c—

area of rail surface subject to convection heat transfer;

T_r—

rail temperature;

T_∞

—

ambient air temperature;

ε

—

emissivity of rail;

σ

—

Stefan-Boltzmann constant;

A_r—

area of rail surface subject to radiation heat transfer;

T_sky—

atmospheric sky temperature above the cloud level;

{dot over (E)}_other—

a term to count for the heat exchange at interfaces of rail-tie and rail-ballast interfaces;

ρ

—

density of rail;

c—

specific heat of rail; and

V—

volume of rail.

21. The method of claim 13, further including measuring an actual temperature of the rail.

22. The method of claim 21, further including updating the predicted future rail temperature using the measured actual temperature of the rail.

23. The method of claim 13, further including processing the meteorological data to estimate current rail temperature, and using the estimated current rail temperature to calculate the future rail temperature.

24. A computer readable medium with instructions for predicting future rail temperature for a rail of a railroad track, the computer readable medium comprising:

instructions for receiving current meteorological data;

instructions for receiving forecasted meteorological data; and

instructions for processing the received current and forecasted meteorological data to calculate a future rail temperature for a future time, accounting for heat transfer characteristics of the rail.

25. The computer readable medium of claim 24, further including instructions for determining a rate of change in rail temperature over time, and instructions for integrating the rate of change in rail temperature over time.

26. The computer readable medium of claim 24, further including instructions for generating a warning signal based on the calculated future rail temperature to indicate the likelihood of the rail buckling at a future time.

27. The computer readable medium of claim 24, further including instructions for periodically receiving updated forecasted meteorological data, and instructions for updating the calculated future rail temperature based on the updated forecasted meteorological data.

28. The computer readable medium of claim 24, wherein the heat transfer characteristics of the rail includes at least one of solar absorptivity of the rail, emissivity of the rail, specific heat of the rail, area of rail surface, and volume the rail.

29. The computer readable medium of claim 24, wherein instructions for calculating the future rail temperature is based on an energy equilibrium model for the rail.

30. The computer readable medium of claim 28, wherein instructions for calculating the future rail temperature includes instructions for determining a rate of change in rail temperature over time in the energy equilibrium model, and instructions for integrating the rate of change in rail temperature over time.

31. The computer readable medium of claim 28, wherein the energy equilibrium model for the rail is represented by equation:

$k<br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\alpha <br><br>}}_s<br><br>A_s<br><br>G_s<br><br>\cos <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\theta <br><br>}-\left(h_{\mathrm{conv}}<br><br>A_c<br><br>\left(T_r-T_{\mathrm{\infty <br><br>}}\right)+\mathrm{\varepsilon <br><br>\sigma <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>A_r<br><br>\left(T_r^4-T_{\mathrm{sky}}^4\right)+{\stackrel{.}{E}}_{\mathrm{other}}\right)=\mathrm{\rho <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{cV}<br><br>\frac{d<br><br>T_r}{d<br><br>t}$

where;

k—

atmospheric filtering factor;

α

_s—

solar absorptivity of rail;

A_s—

area of rail surface exposed to the sun;

G_s—

solar constant;

θ

—

solar angle;

h_conv—

convection coefficient;

A_c—

area of rail surface subject to convection heat transfer;

T_r—

rail temperature;

T_∞

—

ambient air temperature;

ε

—

emissivity of rail;

σ

—

Stefan-Boltzmann constant;

A_r—

area of rail surface subject to radiation heat transfer;

T_sky—

atmospheric sky temperature above the cloud level;

{dot over (E)}_other—

a term to count for the heat exchange at interfaces of rail-tie and rail-ballast interfaces;

ρ

—

density of rail;

c—

specific heat of rail; and

V—

volume of rail.

32. The computer readable medium of claim 24, further including instructions for receiving an actual temperature of the rail.

33. The computer readable medium of claim 32, further including instructions for updating the predicted future rail temperature using the received actual temperature of the rail.

34. The computer readable medium of claim 24, further including instructions for processing the meteorological data to estimate current rail temperature, and instructions for using the estimated current rail temperature to calculate the future rail temperature.