US Patent 7650207 Locomotive/train navigation system and method

In a rail track system having transition points, a locomotive having a navigation system (such as a combined inertial/GPS location system) moves along an initially known track and enters the “halo” surrounding a track transition to begin data collection/logging to accumulate successive position information data points as the locomotive moves into, progresses through, and exits the “halo.” The collected data for movement within the “halo” is then subject to a best fit assessment relative to the data pre-stored in the track database.