Ballast and Subgrade Requirements Study: Railroad Track Substructure - Materials Evaluation and Stabilization Practices

摘要

Earth materials--i.e., soil and rock--form the substructure of all railroad track. In this report, the functions and performance characteristics of each of the substructure elements (i.e., ballast, subballast, and subgrade), and the material properties that influence the substructure performance are described. In addition, guidelines are provided for their use in railroad track.