On the Fundamentals of Track Lateral Resistance

Abstract

A key aspect of track lateral stability assurance is the provision of adequate lateral resistance to the rail-tie structure by the ballast. When lateral resistance is reduced, such as when ballast is worked, the track cannot only lose alignment and surface, but can become buckling prone in the presence of high thermal forces. Current methods to restore ballast strength after track work is through mechanical compaction through dynamic track stabilization (DTS) or through traffic (train load/tonnage) induced consolidation. Research has confirmed the effectiveness of DTS, however, due to the complex nature of ballast compaction mechanics under train loads, a reliable quantification of the effectiveness of train/tonnage based consolidation is still missing. This paper presents a review of the fundamentals of track lateral resistance, its measurement and its key influencing parameters, provides a test/data summary of US measurements to date, present analysis results on influence on track stability, and offers insights on research needs for further research studies for track lateral resistance improvements.