Systems and methods for predictive maintenance of crossings

1. A method comprising:

monitoring an electrical characteristic of a first route when an electric current is injected into the first route, the first route having a crossing intersection with a second route and a crossing signal at the crossing intersection, the electrical characteristic monitored to detect when a vehicle is approaching the crossing intersection on the first route and to determine when to activate the crossing signal at the crossing intersection;

identifying one or more changes in the electrical characteristic of the first route; and

based on the one or more changes that are identified, predicting a failure mode of the first route that interferes with detection of the vehicle approaching the crossing intersection,

wherein the failure mode of the first route that is predicted includes a foreign object shunt conductively coupling the conductive rails of the first route, and wherein the foreign object shunt is predicted as the failure mode responsive to a relationship between the electrical characteristic of the first route and the different locations of the moving shunt created by the vehicle along the first route having a linear portion joined to a non-linear and curved portion of the relationship.

2. The method of claim 1 , wherein the electrical characteristic of the first route that is monitored is at least one of an electrical impedance, a phase of the electric current that is injected into the first route, or a combination of the electrical impedance of the route and the phase of the electric current.

3. The method of claim 1 , further comprising taking one or more remedial actions responsive to predicting the failure mode of the first route.

4. The method of claim 1 , wherein the one or more changes that are identified include changes in at least one of an amplitude or a variance of noise in the electrical characteristic that is monitored.

5. The method of claim 1 , wherein the first route includes plural conductive rails on which wheels of the vehicle travel and into which the electric current is injected, and the electrical characteristic of the first route changes due to the wheels and an axle of the vehicle generating a moving shunt between the conductive rails of the first route.

6. The method of claim 1 , wherein the failure mode that is predicted includes a deterioration of a route-to-wheel interface between the first route and one or more of the wheels of the vehicle when at least one of an amplitude or a variance of noise in the electrical characteristic that is monitored is larger when the vehicle is at locations along the first route that are farther from the crossing intersection than when the vehicle is at locations along the first route that are closer to the crossing intersection.

7. The method of claim 1 , wherein the one or more changes that are identified include a non-linearity in the relationship between the electrical characteristic of the first route and different locations of a moving shunt created by the vehicle along the first route.

8. The method of claim 1 , wherein the failure mode of the first route that is predicted includes an inaccurate calibration of a relationship between the electrical characteristic of the first route and a calibration shunt placed at different locations between conductive rails of the first route prior to travel of the vehicle along the first route.

9. The method of claim 8 , wherein the inaccurate calibration of the relationship is identified responsive to a non-linear and curved relationship between the electrical characteristic of the first route and the different locations of the moving shunt created by the vehicle along the first route.

10. The method of claim 1 , further comprising identifying a location along the first route where the foreign object shunt is located based on where the linear portion of the relationship between the electrical characteristic of the first route and the different locations of the moving shunt created by the vehicle is joined to the non-linear and curved portion of the relationship.

11. The method of claim 1 , further comprising predicting a problem with a moving shunt created by wheels and an axle of the vehicle that conductively couples conductive rails of the first route based on the one or more changes in the electrical characteristic of the first route.

12. The method of claim 11 , wherein the problem with the moving shunt created by the vehicle is predicted responsive to a relationship between the electrical characteristic of the first route and different locations of the moving shunt created by the vehicle having a first curved and non-linear portion for approach of the vehicle to the crossing intersection joined with a second curved and non-linear portion of the relationship for the departure of the vehicle from the crossing intersection.

13. A crossing warning system comprising:

a crossing controller operably coupled to a crossing signal located at a crossing intersection of a first route and a second route, the crossing controller comprising:

a detection module configured to inject an electric current into the first route and monitor an electrical characteristic of the electric current in the first route to determine when a vehicle is approaching the crossing intersection on the first route and to determine when to activate the crossing signal; and

a failure prediction module configured to identify one or more changes in the electrical characteristic of the first route and predict a failure mode of the first route that interferes with detection of the vehicle approaching the crossing intersection based on the one or more changes identified in the electrical characteristic,

wherein the failure mode predicted by the failure prediction module includes a foreign object shunt conductively coupling the conductive rails of the first route, and wherein the foreign object shunt is predicted as the failure mode by the failure prediction module responsive to a relationship between the electrical characteristic of the first route and the different locations of the moving shunt created by the vehicle along the first route having a linear portion joined to a non-linear and curved portion of the relationship.

14. The crossing warning system of claim 13 , wherein the electrical characteristic includes at least one of an electrical impedance, a phase of the electric current that is injected into the first route, or a combination of the electrical impedance and the phase of the electric current.

15. The crossing warning system of claim 13 , further comprising a communication module communicably coupled to the failure prediction module and communicably coupled to a maintenance center to exchange failure mode information between the failure prediction module and the maintenance center, the failure mode information including at least one of the failure mode identified by the failure prediction module, or remedial actions to be taken by the maintenance center in response to the failure mode.

16. The crossing warning system of claim 13 , wherein the first route includes conductive rails on which wheels of the vehicle travel and into which the electric current is injected, and electrical characteristic of the first route changes due to the wheels and an axle of the vehicle generating a moving shunt between the conductive rails of the first route.

17. The crossing warning system of claim 13 , wherein the one or more changes identified by the failure prediction module include a non-linearity in the relationship between the electrical characteristic of the first route and different locations of a moving shunt created by the vehicle along the first route.