Systems and method for controlling warnings at vehicle crossings

1. A method comprising:

receiving one or more absolute times associated with movement of a vehicle system, the one or more absolute times communicated from the vehicle system to notify of at least one of an arrival or departure of the vehicle system at a crossing between a first route being traveled by the vehicle system and a second route, the one or more absolute times specified in accordance with a synchronization scheme used by additional entities in addition to the vehicle system;

modifying at least one of the one or more absolute times into a first relative time, the first relative time specified with reference to a particular event; and

controlling one or more warning devices using the first relative time, the one or more warning devices controlled to at least one of notify one or more other vehicles traveling along the second route of the at least one of arrival or departure of the vehicle system at the crossing or prevent the one or more other vehicles from traveling through the crossing along the second route.

2. The method of claim 1 , further comprising tracking a system time of the one or more warning devices and comparing a difference between the system time and the one or more absolute times received from the vehicle system, wherein the system time is specified by a clock maintained by the one or more warning devices, wherein controlling the one or more warning devices occurs responsive to the difference between the system time and the one or more absolute times received from the vehicle system being no greater than a designated threshold time period, the designated threshold time period based on an amount of time corresponding to the vehicle system traveling at an upper speed limit of the first route to the crossing.

3. The method of claim 1 , further comprising determining if the one or more absolute times received from the vehicle system already has passed and, responsive to determining that the one or more absolute times received from the vehicle system already has passed, communicating a responsive message to the vehicle system that requests one or more additional absolute times from the vehicle system, wherein the one or more additional absolute times are received from the vehicle system and modified into the first relative time that is used to control the one or more warning devices.

4. The method of claim 1 , further comprising tracking a system time of the one or more warning devices, determining whether the system time has been updated within a designated time period, wherein the system time is specified by a clock maintained by the one or more warning devices, and, responsive to determining that the system time has not been updated within the designated time period, communicating a responsive message to the vehicle system that requests one or more additional absolute times from the vehicle system, wherein the one or more additional absolute times are received from the vehicle system and modified into the first relative time that is used to control the one or more warning devices.

5. The method of claim 1 , wherein receiving the one or more absolute times includes receiving plural different absolute times from the vehicle system and modifying the one or more absolute times includes modifying the plural different absolute times into plural different relative times, and wherein controlling the one or more warning devices includes controlling the one or more warning devices based on the first relative time of the plural different relative times that is a shorter time period than one or more other relative times of the plural different relative times.

6. The method of claim 1 , wherein the one or more warning devices include a gate that is activated upon expiration of the first relative time to prevent passage of the one or more other vehicles through the crossing.

7. The method of claim 1 , wherein the one or more warning devices include at least one of a light or a speaker that is activated upon expiration of the first relative time to notify of arrival of the vehicle system at the crossing.

8. The method of claim 1 , wherein the first relative time represents a measurement of a time period extending from a current time until the vehicle system arrives at the crossing.

9. The method of claim 1 , wherein the at least one of the one or more absolute times is modified into the first relative time due to modification of a clock associated with the one or more warning devices causing the at least one of the one or more absolute times to incorrectly indicate when the vehicle system arrives at the crossing.

10. The method of claim 1 , wherein the one or more absolute times are synchronized with at least one of a time provided by a global positioning system or a time provided by a network time protocol.

11. The method of claim 1 , wherein the one or more absolute times are expressed as at least one of coordinated universal time (UTC) or Greenwich mean time (GMT).

12. A system comprising:

a crossing module configured to receive one or more absolute times associated with movement of a vehicle system, the one or more absolute times communicated from the vehicle system to notify of at least one of an arrival or departure of the vehicle system at a crossing between a first route being traveled by the vehicle system and a second route, the one or more absolute times specified in accordance with a synchronization scheme used by additional entities in addition to the vehicle system, wherein the crossing module is configured to modify at least one of the one or more absolute times into a first relative time and to control one or more warning devices using the first relative time, the first relative time specified with reference to a particular event, the one or more warning devices controlled to at least one of notify one or more other vehicles traveling along the second route of the at least one of arrival or departure of the vehicle system at the crossing or prevent the one or more other vehicles from traveling through the crossing along the second route.

13. The system of claim 12 , wherein the crossing module also is configured to compare a difference between a system time tracked by one or more clocks of the one or more warning devices and the one or more absolute times received from the vehicle system, wherein the crossing module also is configured to control the one or more warning devices responsive to the difference between the system time and the one or more absolute times received from the vehicle system being no greater than a designated threshold time period, the designated threshold time period based on an amount of time corresponding to the vehicle system traveling at an upper speed limit of the first route to the crossing.

14. The system of claim 12 , wherein the crossing module also is configured to determine if the one or more absolute times received from the vehicle system already has passed and, responsive to determining that the one or more absolute times received from the vehicle system already has passed, the crossing module is configured to communicate a responsive message to the vehicle system that requests one or more additional absolute times from the vehicle system and, responsive to receiving the one or more additional absolute times from the vehicle system, the crossing module is configured to modify the one or more additional absolute times into the first relative time that is used to control the one or more warning devices.

15. The system of claim 12 , wherein the crossing module is configured to determine when a system time tracked by one or more clocks of the one or more warning devices has been updated within a designated time period, and, responsive to determining that the system time has not been updated within the designated time period, the crossing module is configured to communicate a responsive message to the vehicle system that requests one or more additional absolute times from the vehicle system, to receive the one or more additional absolute times from the vehicle system, and to modify the one or more additional absolute times into the first relative time that is used to control the one or more warning devices.

16. The system of claim 12 , wherein the crossing module is configured to receive the one or more absolute times as plural different absolute times, to modify the one or more absolute times into plural different relative times, and to control the one or more warning devices based on the first relative time of the plural different relative times that is a shorter time period than one or more other relative times of the plural different relative times.

17. The system of claim 12 , wherein the crossing module is configured to at least one of control a gate that is activated upon expiration of the relative time to prevent passage of the one or more other vehicles through the crossing or at least one of a light or a speaker that is activated upon expiration of the first relative time to notify of arrival of the vehicle system at the crossing.

18. The system of claim 12 , wherein the first relative time represents a measurement of a time period extending from a current time until the vehicle system arrives at the crossing.

19. The system of claim 12 , wherein the crossing module is configured to modify the absolute time into the first relative time so that modification of a clock associated with the one or more warning devices causes the absolute time to incorrectly indicate when the vehicle system arrives at the crossing.

20. A system comprising:

a crossing module that includes one or more computer processors configured to receive an absolute time associated with movement of a first vehicle system along a first route toward a crossing between the first route and a second route, the absolute time representing at least one of an arrival time of the first vehicle system at the crossing or a departure time at which the vehicle system is expected to complete passage through the crossing, the absolute time specified in accordance with a synchronization scheme used by additional entities in addition to the vehicle system, wherein the crossing module is configured to modify the absolute time into a relative time, the relative time specified with reference to a particular event; and

one or more warning devices including at least one of a gate or a light, wherein the crossing module is configured to at least one of: activate the gate upon expiration of the relative time to prevent passage of one or more other vehicles through the crossing along the second route, activate the light upon expiration of the relative time to notify the one or more other vehicles of arrival of the first vehicle system at the crossing, or activate the gate to prevent the one or more other vehicles from passing through the crossing along the second route until the relative time indicates that the first vehicle system has completed passage through the crossing along the first route.

21. The system of claim 20 , wherein the crossing module is configured to receive the absolute time from the first vehicle system.

22. The system of claim 20 , wherein the crossing module is configured to compare a difference between a system time of the one or more warning devices and the absolute time received from the vehicle system, wherein the crossing module is configured to control the one or more warning devices responsive to the difference between the system time and the absolute time received from the vehicle system being no greater than a designated threshold time period, the designated threshold time period based on an amount of time corresponding to the vehicle system traveling at an upper speed limit of the first route to the crossing.