Heavy Axle Load Track Substructure Research by TTCI

Abstract

This paper gives an overview of the heavy axle load track substructure research conducted by the Transportation Technology Center, Inc., jointly funded by the Association of American Railroads and the Federal Railroad Administration. As North American railroads are placing increased demands on the track substructure (ballast, subballast, subgrade, and drainage) due to the ongoing trends of increased axle-loads and increased traffic, a significant part of railroads’ track maintenance budget is allocated to cleaning and renewing ballast and correcting rough track caused by track substructure deformation. Poorly performing substructure not only results in high rates of track geometry degradation, but also promotes higher rates of wear and deterioration of the rails, ties, fasteners, and special trackwork. Currently, research activities are focused on the following areas: (1) ballast deterioration study to determine root causes through field investigations and to quantify how track performance is affected by ballast fouling and drainage conditions through laboratory testing; (2) maintenance and remedial methods for correcting and managing track substructure problems; and (3) diagnostics of track substructure problems in developing guidelines for using the ground penetrating radar technologies by North American railroads.