TrackSafe: a track geometry car based real-time dynamics simulator

Recently, there has been a movement in the railroad industry to begin assessing track geometry and track safety on the basis of real-time predictions of rail vehicle behavior in response to track geometry measurements while on board a track geometry car running at full track speed. With support from the Federal Railroad Administration, ZETA-TECH Associates, Inc. has developed a system for this purpose called TrackSafe. TrackSafe uses a simplified mechanical model of a rail vehicle driven by track geometry inputs to find and locate areas in track that may result in poor or unsafe dynamic vehicle response. The model is so computationally efficient that it is possible to conduct more than 80 simultaneous simulations when the track geometry vehicle is moving at full speed on Class 5 track (80 mph). This allows the track assessment to be performed on the basis of multiple car types each being simulated at a full range of operating speeds. The importance of testing at a full range of speeds and for a wide variety of vehicle types has been demonstrated repeatedly with TrackSafe, both in off-line analysis and in live real-time testing followed by on the ground inspections and validations. Several off-line investigations using older geometry data have also shown the ability of this system to find and locate the sections of track where derailments took place. These have often been in locations where no FRA geometry defect exists for posted track speed, but due to repeated or combined geometry deviations, poor behavior is predicted to occur, in some cases at speeds less than posted speed. This paper presents the results from recent testing and evaluation of TrackSafe including observations from recent on-the-ground validations. In particular, this paper will present the results of a derailment investigation and the first implementation of the system on a U.S. Class I freight railroad's track geometry vehicle. The results presented here are intended to demonstrate the ability of TrackSafe to accurately identify those locations in track that are likely to lead to potentially unsafe vehicle response using comprehensive testing of multiple vehicle types each at a full range of operating speeds. It is through increased awareness and growing confidence that the railroad industry will begin to embrace this new and powerful method for derailment prevention.