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Throughout the international railway community, there are many different designs of elastic fastening systems that have been developed to meet a variety of design specifications and performance expectations. Historically, in North America, the most common types of fastening systems used for concrete crossties are the Safelok I or e-clip systems. In recent years railroads have begun implementing the Skl-style (W) fastening system with concrete crossties in existing and new heavy haul freight railroad mainlines. The magnitude of lateral force applied to the Skl-style fastening system is important information for both design and application purposes. Despite this importance, the lateral force applied to the Skl-style fastening system in a heavy haul freight railroad environment has never been quantified to date. To better understand how the Skl-style system performs under the magnitude of lateral loads observed on heavy haul freight railroads, research was conducted by the Rail Transportation and Engineering Center (RailTEC) at the University of Illinois at Urbana-Champaign (UIUC). The focus of this paper is on laboratory characterization of the lateral load path through the Skl-style fastening system using novel instrumentation techniques that are subjected to heavy haul freight railroad loading conditions. The investigation of fastening system performance included an evaluation of lateral load distribution through the track superstructure, and a single fastening system. Laboratory experimentation concluded that lateral wheel load is primarily distributed to three crossties, the relationship between lateral wheel load and lateral force resisted by field side angled guide plate is non-linear, and that the design of the Skl-style fastening system allows lateral force to be transferred into the crosstie below the worst case concrete compressive fatigue strength. The observations from this study will assist the rail industry in improving fastening system design and developing mechanistic track structure design method.

A sustained increase in heavy axle loads and cumulative freight tonnages, coupled with increased development of high-speed passenger rail, is placing an increasing demand on railway infrastructures. Some of the most-critical areas of the infrastructure in need of further research are track components used in high-speed passenger, heavy haul and shared infrastructure applications. In North America, many design guidelines for these systems use historical wheel loads and design factors that may not necessarily be representative of the loading currently experienced on rail networks. Without a clear understanding of the nature of these loads and how design processes reflect them, it is impossible to adequately evaluate the superstructure in order to make design improvements. Therefore, researchers at the University of Illinois at Urbana-Champaign are conducting research to lay the groundwork for an improved and thorough understanding of the loading environment imparted into the track structure using wheel loads captured by wheel impact load detectors. This paper identifies several design factors that have been developed internationally, and evaluates their effectiveness based on wheel loads using several existing and new evaluative metrics. New design factors are also developed to represent the wheel-loading environment in a different manner. An evaluative approach to historical and innovative design methodologies will provide improvements to designs, based on actual loading experienced on today’s rail networks.

A railroad sleeper and fastening system is composed of many unique parts that, when assembled, attempt to distribute train wheel loads through the system without damaging the components while providing a safe running surface and track geometry for trains to operate on. In order to evaluate the health of the sleeper and fastening system, there are many areas that need to be examined to ensure that key limit states are not exceeded. One key area of concern is the sleeper rail seat, specifically the load magnitude applied to this surface. There are many different metrics to evaluate the rail seat load, and this report will compare these to determine which should be used given different operating and infrastructure conditions. A sample calculation for each methodology was completed in order to compare how the methods differ, and to more fully understand the strengths and limitations of each methodology. These calculations were completed both with a static load and dynamic load, as the individual approaches account for dynamic loads in a variety of ways. For the purpose of this report, these calculations were completed assuming a concrete sleeper infrastructure. The goal of this paper is to provide an evaluation of the existing rail seat load calculation methodologies to improve current concrete sleeper and fastening system design standards through the application of mechanistic design principles.

In North America, many design guidelines for track components in shared-use railway infrastructure use historic wheel loads that may not necessarily be representative of those seen on rail networks today. Without a clear understanding of the nature of these loads, it is impossible to evaluate the superstructure adequately to make design improvements. Therefore, researchers at the University of Illinois at Urbana–Champaign are conducting research to lay the groundwork for an improved and thorough understanding of the loading environment entering the track structure. Wheel impact load detectors (WILDs) have been used in North America for decades to identify defective wheels that could damage the rail infrastructure or result in a rolling stock failure. Information regarding loads obtained from a WILD can be used to identify trends that not only provide a clearer picture of the existing loading environment created by widely varied traffic characteristics but also can be used in future design and maintenance planning of infrastructure according to the anticipated traffic. The current trends in wheel loads across the North American rail network are discussed, and the effects of speed and other sources of load variability are investigated. In addition to WILD data, instrumented wheel set data were used to gain insight into loading conditions, and preliminary analyses of these data are included. Ultimately this work will lead to useful distinctions of loads for improved design methodologies that are specific to the intended type of traffic traversing a given route or network.

A sustained increase in heavy axle loads and cumulative freight tonnages, coupled with increased development of high speed passenger rail, is placing an increasing demand on railway infrastructure. Some of the most critical areas of the infrastructure in need of further research are track components used in high speed passenger, heavy haul, and shared infrastructure applications. In North America, many design guidelines for these systems use historical wheel loads that may not necessarily be representative of those seen on rail networks today. Without a clear understanding of the nature of these loads, it is impossible to adequately evaluate the superstructure to make design improvements. Therefore, researchers at the University of Illinois at Urbana-Champaign (UIUC) are conducting research to lay the groundwork for an improved and thorough understanding of the loading environment entering the track structure. Wheel impact load detectors (WILDs) have been used in North America for decades to identify bad-acting wheels that could damage the rail infrastructure or result in a rolling stock failure. The WILD measures vertical and lateral rail loads imparted by the wheel at the wheel-rail interface, along with other pertinent information related to the specific wheel, car, and train passing the instrumented site. This information can be used to identify and classify trends in the loading features and other characteristics of the rolling stock. These trends not only provide a clearer picture of the existing loading environment created by widely varied traffic characteristics, but can be used in future design and maintenance planning of infrastructure according to the anticipated traffic. This paper will discuss the current trends in wheel loads across the North American rail network while investigating the effects of speed on dynamic and impact loads. Ultimately this work should lead to useful distinctions of loads for improved design methodologies that are specific to the intended type of traffic traversing a given route or network.Copyright © 2013 by ASME