A sustained increase in gross rail loads and cumulative freight tonnages, as well as increased interest in high and higher-speed passenger rail development in the United States, is placing an increasing demand on railway infrastructure. According to a railway industry survey conducted by the University of Illinois at Urbana-Champaign (UIUC), rail seat deterioration (RSD) was identified as one of the primary factors limiting concrete crosstie service life. Therefore, it can be seen that there is a need for infrastructure components with increased strength, durability, and ability to maintain the tighter geometric track tolerances under demanding loading conditions. Researchers have hypothesized that localized crushing of the concrete rail seat is one of five potential mechanisms that contribute to RSD. Therefore, to better understand this mechanism, UIUC is utilizing a matrix based tactile surface sensor (MBTSS) to quantify the forces acting at the interface between the bottom of the rail pad and the concrete tie rail seat. The MBTSS measures the forces and distribution of pressure as a load is applied to the rail seat. Preliminary laboratory testing has shown that higher modulus rail pads distribute forces poorer than lower modulus rail pads, leading to localized areas with high contact pressure and a higher probability of crushing. Testing has also shown that as the lateral/vertical (L/V) force ratio increases, the pressure on the field side of the rail seat also increases, possibly accelerating RSD. The objective of future field testing is to be able to validate the assumptions made from this preliminary laboratory data. Data collected and analyzed throughout this research project will provide valuable insight into developing future concrete crosstie and fastening system component designs that meet the operational and loading demands of high speed rail and joint passenger/freight corridors.

Special trackwork, including turnouts and crossing diamonds and their components, plays a vital role in railway infrastructure by providing route flexibility to trains as they travel across a network. As the interest in shared rail corridors involving heavy-axle-load freight traffic and high-speed-rail passenger traffic grows, special trackwork represents a significant challenge due to diverging loading characteristics and design priorities. This paper presents an overview of the issues related with special trackwork for shared rail corridors, as well as an in-depth analysis of the relevant research to date. The relevance of different shared operation types and research needs are also presented. This study can be used to assist in the planning of new passenger services on freight rail lines, or vice versa, in the USA, and may also be relevant to shared rail corridor development in other countries.

A sustained increase in gross rail loads and cumulative freight tonnages as well as growing interest in high-speed passenger rail development is placing an increasing demand on North American railway infrastructure. To meet this demand, improvements to the performance and durability of concrete crossties and fastening systems are necessary. One of the typical failure modes for concrete crossties in North America is rail seat deterioration, and researchers have hypothesized that localized crushing of the concrete in the rail seat is one of the potential mechanisms that contributes to this failure mode. To understand this mechanism better, the University of Illinois at Urbana–Champaign is using a matrix-based tactile surface sensor to measure and quantify the forces and pressure distribution acting at the contact interface between the concrete rail seat and the bottom of the rail pad. Preliminary data collected during laboratory experimentation have shown that a direct relationship existed between rail pad modulus and maximum rail seat pressure. In addition, under a constant vertical load, a direct relationship between the lateral-to-vertical force ratio and the maximum field side rail seat pressure was observed. Given that all preliminary results indicate that various combinations of pad modulus, track geometry, and lateral-to-vertical force ratio create localized areas of high pressure, crushing remains a potential mechanism leading to rail seat deterioration. Through the analysis of rail seat pressure data, valuable insight can be gained that can be applied to the development of designs for concrete crosstie and fastening system components that meet current and projected service demands.