Objective Track Quality Indices

Abstract

A set of new track quality indices (TQIs) has been developed to aid in the evaluation of track geometry measurements and to complement the well-established track classification based on the Federal Track Safety Standards (FTSS). The newly developed TQIs will be eventually implemented as real-time processed indicators on FRA's research vehicle, the T-16. After a review of existing methods for determining TQIs, it is concluded that none of the current methods can satisfy the stated objectives. Therefore, a new methodology has been developed and tested to compute TQIs from track geometry data based on a simple and intuitive approach. The results have shown that the new TQIs can quantitatively describe the relative condition of track surface geometries. Furthermore, it is shown that the new TQIs are well correlated to the FTSS for each track class, providing a relative indication of quality within each class. A total of 48 track geometry surveys are selected from measurements taken by the FRA T-2000 track geometry car. Track geometry data from these surveys are processed and divided into 528-ft segments. For each track segment, the FTSS is used to determine actual track class. The track segments are grouped according to the actual classes these segments meet. Track quality indices are computed over each track segment. The results are used to establish TQI thresholds for each track class. The findings indicate that there are distinct TQI ranges for each track class, although there is some overlap between the upper boundary of one class and the lower boundary of the next.