Rail collision threat detection system

1. A detection system comprising:

a transmitter associated with a first train and configured to emit an end-of-train signal; and

a receiver associated with the transmitter and the first train and configured to:

receive the end-of-train signal from the transmitter;

receive at least one remote signal from a second train;

detect a signal strength of the remote signal;

determine a relative distance of the second train from the first train based on the signal strength of the remote signal; and

determine whether the second train is a collision threat to the first train based on the remote signal from the second train.

2. The detection system of claim 1 , wherein a communication frequency at which the receiver is configured to receive signals is the same frequency used by both the first and second train for end-of-train communications.

3. The detection system of claim 1 , wherein the remote signal comprises an end-of-train signal from a second transmitter associated with the second train.

4. The detection system of claim 3 , wherein the remote signal further includes a track identifier, and the receiver is configured to determine whether the second train is a collision threat based on the track identifier and a track on which the first train is located.

5. The detection system of claim 1 , wherein the receiver is configured to:

determine whether the second train is within a warning range of the receiver; and

in the event the second train is within the warning range, identify the collision threat based on the relative distance and the speed of the second train.

6. The detection system of claim 5 , further including:

a warning system configured to notify at least one of a dispatch and a train operator of the collision threat; and

a braking controller configured to initiate a braking force of the first train.

7. A method for detecting a collision threat between a first train and a second train comprising:

receiving on the first train a signal from the second train;

detecting a signal strength of the signal;

determining a relative distance between the first train and the second train based on the signal strength; and

identifying whether the second train is a collision threat to the first train based on the relative distance.

8. The method of claim 7 , further including:

notifying at least one of a dispatch and an operator of the first train of the collision threat; and

sending a command to initiate a braking force of the first train.

9. The method of claim 8 , further including identifying an occupied track, wherein the signal is indicative of a track on which the first train is travelling and identifying whether the second train is a collision threat is further based on whether the track on which the second train is travelling is the same as the occupied track.

10. The method of claim 9 , further including:

identifying a home train; and

determining whether the signal is received from the home train, wherein the signal is indicative of a train identifier.

11. The method of claim 9 , further including:

determining the second train is approaching on a second track based on the relative distance;

determine a time at which the home train and the train will pass based on the relative distance and the relative speed; and

notifying the dispatch that the second train and the home train will pass one another.

12. The method of claim 7 , further including:

receiving a second signal from the second train;

detecting a second signal strength of the second signal; and

determining a relative speed of the second train based on a time between receiving the first and second signals and the difference between the first and second signal strength, wherein identifying whether the second train is a collision threat is further based on the relative speed of the second train.

13. The method of claim 12 , further including determining a travel direction of the second train based on the relative speed of the second train and the second signal strength, wherein identifying whether the second train is a collision threat is further based on the travel direction of the second train.

14. A first train comprising:

a locomotive;

a transmitter associated with at least one of the locomotive and a trailing railcar and configured to emit an end-of-train signal; and

a receiver associated with the locomotive and configured to:

receive the end-of-train signal from the transmitter;

receive a remote signal from a second train;

detect a signal strength of the remote signal;

determine a relative distance of the second train from the first train based on the signal strength of the remote signal; and

determine whether the second train poses a collision threat to the first train based on the remote signal.

15. The first train of claim 14 , wherein a communication frequency at which the receiver is configured to receive signals is the same frequency used by both the first and second train for end-of-train communications.

16. The first train of claim 14 , wherein the remote signal comprises an end-of-train signal from a second transmitter associated with the second train.

17. The first train of claim 16 , wherein the second signal further includes a track identifier, and the receiver is configured to determine whether the second train is a collision threat based on the track identifier and a track on which the second train is travelling.

18. The train of claim 14 , wherein the receiver is configured to:

receive a second remote signal from the second train;

detecting a second signal strength of the second remote signal; and

determine a travel direction of the second train based on the relative speed of the second train and the second signal strength.