Evaluation of Laboratory and Field Experimentation Characterizing Concrete Crosstie Rail Seat Load Distributions

As higher demands are placed on North American railroad infrastructure by heavy haul traffic, it is increasingly important to understand the factors affecting the magnitude and distribution of load imparted to concrete crosstie rail seats. The rail seat load distribution is critical to the analysis of failure mechanisms associated with rail seat deterioration (RSD), the degradation of the concrete surface at the crosstie rail seat. RSD can lead to wide gauge, cant deficiency, and an increased risk of rail rollover, and is therefore of primary concern to Class I Freight Railroads in North America. Researchers at the University of Illinois at Urbana-Champaign (UIUC) have successfully characterized the loading environment at the rail seat using matrix-based tactile surface sensors (MBTSS). Previous research has proven the feasibility of using MBTSS in both laboratory and field applications, and recent field experimentation has yielded several hypotheses concerning the effect of fastening system wear on the rail seat load distribution. This paper will focus on the analysis of data gathered from laboratory experimentation with MBTSS to evaluate these hypotheses, and will propose a metric for crosstie and fastening system design which considers the uniformity of the load distribution. The knowledge gained from this experimentation will be integrated with associated research conducted at UIUC to form the framework for a mechanistic design approach for concrete crossties and fastening systems.