On the Use of Ballast Inspection Technology For the Management of Track Substructure

Abstract

The railroad track substructure and specifically its ballast and sub-ballast layers play a key role in the maintenance of the stability and geometry of the track structure. However, because it traditionally has not been readily accessible below the surface of the ballast, very limited information about its conditions was available, without extensive and disruptive excavation techniques. New-generation inspection technology now allows for the access to significant additional information about the ballast and sub-ballast to include its extent, condition, depth, degree of fouling, and any inadequacies in the substructure layer that can lead to loss of track stability or accelerated degradation of the track structure. This paper discusses several of the key track substructure inspection technologies, to include the traditional monitoring of the track geometry and then addresses the new inspection technologies now available to more accurately define the ballast condition. This includes such newly introduced inspection technologies as LIDAR for measurement of the ballast profile, ground penetrating radar inspection for ballast depth deficiency, and other related inspection technologies. These new technologies allow for more accurate ballast deficit and condition analysis.