TTC OPERATED BY ENSCO
Ballast Studies at the Transportation Technology Center New technology is telling us more about ballast Radim Bruzek, R&D Program Manager, ENSCO, Inc., Springfield, VA Sean Woods, R&D Project Manager, ENSCO, Inc., Pueblo, CO Hugh Thompson, Program Manager, Track Research Division, Federal Railroad Administration Office of Research, Development, and Technology, Washington, DC
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ver the years, the Federal Railroad Administration (FRA) has taken an active role in sponsoring numerous research projects aimed at enhancing the understanding of ballast behavior and performance. These initiatives sought to tackle the challenges associated with ballast inspection, condition assessment, and remediation. One of the primary objectives of this research has been to develop innovative techniques and technologies for the inspection and assessment of ballast conditions. By exploring advanced methods such as ground-penetrating radar (GPR), laser scanning, and machine learning algorithms, researchers aim to enhance the accuracy and efficiency of ballast inspection processes. These advancements can help identify hidden defects, such as fouling, contamination, or irregularities, that are not easily
or efficiently detected through traditional visual inspections. FRA support for research in this field demonstrates its commitment to improving the overall reliability and safety of railway infrastructure. This article highlights a few recent examples of research projects conducted at FRA’s Transportation Technology Center (TTC) in Pueblo, Colorado. These initiatives have advanced ballast inspection and condition assessment and led to innovative technologies for enhancing the performance and safety of railroad ballast. Due to its location in the Colorado high desert, the TTC does not fully represent all track and ballast conditions found throughout the U.S. Nevertheless, as a self-contained railroad operating environment, it has demonstrated its uniqueness and high value as a facility for conducting a wide range of research activities, including
those pertaining to railroad ballast. Railroad ballast plays a crucial role as an interfacial component that carries and transfers the load from the crossties to the sub-ballast and the underlying subgrade. In addition to the capacity to sustain loads, ballast must be able to maintain track geometry and provide adequate drainage for the track. Together with other track components, it forms an integral part of the vehicletrack system. The current federal regulation concerning ballast is defined in Title 49, Code of Federal Regulations, § 213.103Ballast; general. The rule provides qualitative requirements for ballast performance, but it does not regulate the structural design of ballast layer thickness and physical properties necessary to limit track settlement and the formation of track geometry variations. Inadequate design, defined as the “inability to meet the requirements of the rule,” means that the track structure might not be able to withstand the applied load. The rule is a non-class specific rule that requires defective track taken out of service if not repaired within 30 days. Fouling is the principal cause of noncompliant ballast. Fouling can prevent the adequate drainage required by the regulation. Fouling material can come from above (e.g., spillage from railcars or blown in from surrounding property), from internal breakdown of ballast rock, and from infiltration
Figure 1: 3D point cloud collected by the LiDAR system clearly captures an artificial ballast slope defect
4 Railway Track & Structures // September 2023
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