A system for determining a possible location of a train in a track network including interconnected tracks having wayside devices associated with these tracks. The system includes a positioning system for determining an estimated location area of a train and a track database having track location data. A computer: obtains the determined estimated location area of the train from the positioning system; identifies a plurality of tracks in the estimated location area of the train, based upon the track location data; obtains signal system data for at least one wayside device associated with at least one of the tracks identified within the estimated location area; and determines at least one possible train location on at least one of the identified tracks based at least in part upon the obtained signal system data. A method and apparatus for determining the possible location of a train is also provided.