Analysis of the Relationship Between Rail Seat Load Distribution and Rail Seat Deterioration in Concrete Crossties

One of the most common failure modes of concrete crossties in North America is the degradation of the concrete surface at the crosstie rail seat, also known as rail seat deterioration (RSD). Loss of material beneath the rail can lead to wide gauge, rail cant deficiency, and an increased risk of rail rollover. Previous research conducted at the University of Illinois at Urbana-Champaign (UIUC) has identified five primary failure mechanisms: abrasion, crushing, freeze-thaw damage, hydro-abrasive erosion, and hydraulic pressure cracking. The magnitude and distribution of load applied to the rail seat affects four of these five mechanisms; therefore, it is important to understand the characteristics of the rail seat load distribution to effectively address RSD. As part of a larger study funded by the Federal Railroad Administration (FRA) aimed at improving concrete crossties and fastening systems, researchers at UIUC are attempting to characterize the loading environment at the rail seat using matrix-based tactile surface sensors (MBTSS). This instrumentation technology has been implemented in both laboratory and field experimentation, and has provided valuable insight into the distribution of a single load over consecutive crossties. A review of past research into RSD characteristics and failure mechanisms has been conducted to integrate data from field experimentation with existing knowledge, to further explore the role of the rail seat load distribution on RSD. 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.

The Effect of Deformation on Mechanical Properties and Shakedown on Railroad Wheels

Plastic deformations alter the mechanical properties of many metals and alloys. Class C and Class D wheel steels such as are used in North American freight car service are particularly affected by plastic deformations occurring during rolling contact between the wheel tread and rail head. This investigation determines the effect plastic deformations have on the mechanical properties of Class C and D wheel steels and how those changes could relate to shakedown theory. The effect of temperature is also discussed.

Ultrasonic Tomography for Rail Flaw Imaging

There is a need in the railroad industry to have quantitative information on internal rail flaws, including flaw size and orientation. Such information can lead to knowledge-based decision making on any remedial action, and ultimately increase the safety of train operations by preventing derailments. Current ultrasonic inspection methods leave such sizing determinations to the inspector, and there can be significant variability from one inspector to another depending on experience and other factors. However, this quantitative information can be obtained accurately by 3-D imaging of the rail flaws. It is the goal of this project to develop a portable system that will improve defect classification in rails and ultimately improve public safety. This paper will present a method for 3-D imaging of internal rail flaws based on Ultrasonic Tomography. The proposed technique combines elements of ultrasonic testing with those of radar and sonar imaging to obtain high-resolution images of the flaws using a stationary array of ultrasonic transducers. The array is operated in a “full matrix capture” scheme that minimizes the number of ultrasonic transmitters, hence simplifying the practical implementation and reducing the inspection time. In this method, a full 3D image of the rail volume identifies the location, size and orientation of the defect. This will help to eliminate human error involved with a typical manual inspection using a single transducer probe inspection. The results of advanced numerical simulations, carried out on a rail profile, will be presented. The simulations show the effectiveness of the technique to image a 5% Head Area Transverse Defect in the railhead. Current efforts are aimed at developing an experimental prototype based on this technology, whose design status is also discussed in this paper.

Lateral Impact of Railroad Bridges With Hybrid Composite Beams: Finite Element Modeling and Preliminary Dynamic Behavior Study of HCB

Grade separations have been used along High-Speed Rail (HSR) to decrease traffic congestion and the danger that occurs at grade crossings. However, the concern with grade separations is the potential damage due to lateral impact of bridge superstructures by over-height vehicles. This is a concern with existing bridges, and lateral impact is not included in standard bridge code provisions. A new bridge technology, Hybrid Composite Beam (HCB), was proposed to meet the requirements of another HSR objective, that of a sustainable solution for the construction of new and replacement bridges in rail infrastructure. The hybrid composite beam combines advanced composite materials with conventional concrete and steel to create a bridge that is stronger and more resistance to corrosion than conventional materials. The HCB is composed of three main parts; the first is a FRP (fiber reinforced polymer) shell, which encapsulates the other two parts. The second part is the compression reinforcement which consists of concrete or cement grout that is pumped into a continuous conduit fabricated into the FRP shell. The third part of the HCB is the tension reinforcement that could consist of carbon or glass fibers, prestressed strands, or other materials that are strong in tension, which is used to equilibrate the internal forces in the compression reinforcement. The combination of conventional materials with FRP exploits the inherent benefits of each material and optimizes the overall performance of the structure. The behavior of this novel system has been studied during the last few years and some vertical static tests have been performed, but no dynamic or lateral impact tests have been conducted yet. Therefore, the main objective of this study is to evaluate the performance of HCB when subjected to lateral impact loading caused by over-height vehicles. This paper explains the advantages of HCB when used in bridge infrastructures. The commercial software ABAQUS was used to perform the finite element (FE) modeling of a 30ft long HCB. Test data was used to validate the results generated by FE analysis. A constant impact loading with a time duration of 0.1 second was applied to an area at the mid-span of the HCB. Lateral deflection and stress distribution were obtained from FE analysis, and local stress concentration can be observed from the stress contour. Full-scale beam dynamic testing will be conducted in the future research to better study the behavior of HCB when subjected to over-height vehicles.

Design Concepts for the Next Generation of High-Speed Diesel-Electric Locomotives

The Passenger Rail Investment and Improvement Act (PRIIA) Section 305 Next Generation Equipment Committee’s specification for diesel-electric locomotives has several challenging requirements. Among these is limiting P2 Force to 82,000 pound force (lbf) at 125 miles per hour (mph). To achieve this, the locomotive designer would have to balance unsprung mass and axle load. A design envelope exists within which that balance can be achieved. Advanced designs of traction and braking systems are required, and attention has to be paid to minimizing the overall mass of the locomotive.

Rail Highway Grade Crossing Roughness Quantitative Measurement Using 3D Technology

Quality of surface is an important aspect affecting both the safety and the performance of at-grade rail-highway crossings. Roughness may increase the risk of crashes for both trains and automobiles. Varying grades in crossing profiles increase the likelihood of high-centered crossing collisions between train and truck [1]. The US DOT Railroad Highway Grade Crossing Handbook [2] suggests that rough surfaces could distract a driver’s attention from oncoming trains and that the unevenness of the crossing could result in a driver losing control of their vehicle resulting in a crash. No quantitative method currently exists to quickly and economically assess the condition of rail crossings in order to evaluate the long term performance of crossings and set a quantitative trigger for their rehabilitation. The conventional method to measure the surface of quality of crossings is based on expert judgment, whereby crossing surfaces are classified as poor, fair or good after an inspector visits and drives over the crossing. However, actual condition of the crossing could be different from the subjective rating. Poor condition rating crossings may not always present the most cost-effective locations for preventive maintenance to lower overall life-cycle costs. Conventional ratings may derive from driving a passenger car of pickup once over the crossing. Effects of various speed, on various vehicles (suspension), and at various places (laterally) cannot be determined or even estimated except at the smoothest of crossings. A quantifiable and extensible procedure is desired. With rapid advances in computer science, 3D sensing and imaging technologies, it seems logical that a cost-effective quantitative method could be developed to determine the need to rehabilitate rail crossings and assess long term performance. Fundamental to the quantification of crossing condition is the acquisition of an accurate 3D surface model of the crossing in its present state. This paper reports on the development of an accurate, low cost and readily deployable sensor capable of rapid collection of this 3D surface. The research is seen as a first step towards automating the crossing inspection process, ultimately leading to the quantification and estimation of future performance of rail crossing.

FRA Autonomous Track Geometry Measurement System Technology Development: Past, Present, and Future

The Federal Railroad Administration’s (FRA’s) Office of Research and Development has undertaken a multi-phase research program focused on the development and advancement of Autonomous Track Geometry Measurement Systems (ATGMS) and related technologies to improve rail safety by increasing the availability of track geometry data for safety and maintenance planning purposes. Benefits of widespread use of ATGMS technology include reduced life-cycle cost of inspection operations, minimized interference with revenue operations, and increased inspection frequencies. FRA’s Office of Research and Development ATGMS research program results have demonstrated that the paradigm of track inspection and maintenance practices, information management and, eventually, government regulations will change as a result of widespread use of ATGMS technology by the industry. A natural consequence of increased inspection frequencies associated with ATGMS is the large amount of actionable information produced. Therefore, changing existing maintenance practices to address a larger number of identified track issues across large geographic areas will be a challenge for the industry. In addition, managing ATGMS data and assessing the quality of this information in a timely manner will be challenging. This paper presents an overview of the FRA’s ATGMS research program with emphasis on its evolution from a proof-of-concept prototype to a fully operational measurement system. It presents the evolution of ATGMS technology over time including the development of a web-based application for data editing, management and quality assurance. Finally, it presents FRA’s vision for the future of the ATGMS technology.

A Graphical User Interface for Contacts Between Wheel and Rail

Analysis of contact points between wheel and rail during the wheel climb is of interest to railroad application engineers. In this study the climb maneuver of a wheelset is modeled in a general purpose multi-body system computer program. This model then is used to generate the contact data for a climbing wheelset. A graphical user interface is developed which uses this contact data and generates several contact points charts. In developing the graphical user interface, mouse and keyboard events as well as other controls are used to make the interface interactive and intuitive.

A Comprehensive Framework for Assessing Passenger Rail Services: A Case Study of the Hoosier State Line

The development of a nationwide commuter and high-speed rail (HSR) network has been suggested as a promising and “greener” passenger transport solution with the potential to reduce energy consumption and greenhouse gas emissions, given efficient planning that will ensure sufficient ridership and sustainable investment. It is anticipated that passenger rail growth will bring regional economic benefits as well as promote energy independence, transportation safety, and livable communities with improved accessibility and inter-connectivity. Much research has been conducted to identify the benefits and costs associated with the operation, maintenance, and improvement of passenger rail services. However, previous studies supporting investment in passenger rail have generally considered one evaluation factor at a time. Additionally, studies suggesting that investment in passenger rail is not cost-effective give more weight to quantifiable benefits and current conditions, and rarely consider changes in public preferences influenced by policies and fostered conditions to encourage mode shifts. Thus, the literature lacks a comprehensive approach that would evaluate investments in passenger rail, accounting for quantifiable and other benefits, in light of environmental, resilience and sustainability, economic, demand, and feasibility factors. Using a case study of the Hoosier State line, this study illustrates a systems approach for comprehensively assessing passenger rail services in the United States in terms of the system’s existing opportunities and future directions. The Hoosier State line operates four days per week between Indianapolis, Indiana and Chicago, Illinois with four intermediate stops. As of October 1, 2013, the State of Indiana, local communities, and Amtrak reached an agreement to support the Hoosier State line for the next fiscal year (2013–2014).

Laboratory and Field Investigation of the Rail Pad Assembly Mechanistic Behavior

To achieve the performance demands due to growing heavy-haul freight operations and increased high-speed rail service worldwide, advancements in concrete crosstie fastening systems are required. A mechanistic design approach based on scientific principles and derived from extensive laboratory and field investigation has the potential to improve the current best practices in fastening system design. The understanding of failure modes and effects on each component, associated with an improved understanding of load distribution and mechanical behavior, will ultimately increase production and operational efficiency while reducing unscheduled maintenance, track outages, and unplanned additional costs. Improvements on the rail pad assemblies, the components responsible for attenuating loads and protecting the concrete crosstie rail seat, will enhance the safety and efficiency of the track infrastructure. Understanding the mechanistic behavior of rail pad assemblies is critical to improving the performance and life cycle of the infrastructure and its components, which will ultimately reduce the occurrence of potential failure modes. Lateral, longitudinal, and shear forces exerted on the components of the fastening system may result in displacements and deformations of the rail pad with respect to the rail seat and rail base. The high stresses and relative movements are expected to contribute to multiple failure mechanisms and result in an increased need for costly maintenance activities. Therefore, the analysis of the mechanics of pad assemblies is important for the improvement of railroad superstructure component design and performance. In this study, the lateral displacement of this component with respect to the rail base and rail seat is analyzed. The research ultimately aims to investigate the hypothesis that relative displacement between the rail pad and rail seat occurs under realistic loading environments and that the magnitude of the displacement is directly related to the increase in wheel loads.