the present invention is used within a rail yard or known location unique yard position data is transmitted from the transmitter 24 thus if used within a rail yard in an exemplary embodiment then the unique yard position data is transmitted to the wayside mounted receiver 28 whereas if the present invention is used along a railway network milestone or milepost position data is transmitted back to the train more than likely the locomotive where the receiver 30 is located though the wayside mounted receiver 28 is discussed above as being located within a rail yard those skilled in the art however will also recognize that wayside mounted receivers 28 may also be used within a railway network so as to provide train location data to a wayside device 33 for use in performing a defined function in operation when used in a rail network where the locomotive 31 may need to acquire real time accurate train position data the present invention with autonomously provide milepost data whenever the wheels 22 of a train 31 passes over the present invention the train 31 is then able to pass off this milepost data to its systems and or sub systems that require such information to insure reliability redundancy sequence numbers and or source data bits built in tests bits may also be added for improved data integrity as needed for safety critical decisions that utilizes position data it is important that the integrity of the position data be commensurable to the hazard risk associated with the use of the position data when the present invention is installed within a rail yard or hump yard the present invention will autonomously generate a signal 26 encoded with specific yard position data.