TECHNICAL DATA BASES REPORT. BALLAST AND FOUNDATION MATERIALS RESEARCH PROGRAM

Literature and other information sources pertaining to properties of granular materials, ballast and sub-ballast materials, fine-grained soils, and structural behavior models were reviewed. Presented in this report is a summary of the current technology relative to the following: (1) procedures for evaluating ballast and subgrade material properties; (2) factors which influence ballast and soil material properties; (3) relations between ballast and soil material properties and track system behavior and performance; (4) applicability of structural analysis models to predicting behavior of track system; (5) transfer functions relating track behavior to performance. Based on the review, it is concluded that ballast and subgrade materials receive inadequate considerations in analysis and design, more realistic models are available for structural analysis of track systems, transfer functions relating track behavior to performance are not available and climatic factors exert a significant influence on behavior and performance and must be given appropriate consideration in analysis and design of the track system.