Field Study of Load Path in Rail and Concrete Crosstie System

The design and performance of concrete ties and elastic fastening systems must be improved to meet demands placed on North America’s railway infrastructure through ever-increasing freight tonnages and development of its high speed rail program. In July 2012, a field experimentation program was performed at the Transportation Technology Center (TTC) in Pueblo, CO by researchers from the University of Illinois at Urbana-Champaign (UIUC). This paper focuses on the transfer of vertical and lateral loads through the system, demonstrating the demands of the fastening components (e.g. insulators, fastening clips) and concrete crossties.  Measurements of loads, strains and displacements were used to quantify the physical response of the system under various parameters (track curvature, train speed, and car weight). The experimental data provide validation for a comprehensive finite element model developed by UIUC. Improvements to instrumentation strategies and areas of uncertainty will also be discussed. These experimental results will be used to guide future research in further quantifying the field loading demands, ultimately leading to a mechanistic design approach for the concrete crosstie and components within the fastening system.