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.

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.

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.

Advances in Bonded Insulated Rail Joints to Improve Product Performance

Insulated rail joints (IJs) are critical components of railroad track infrastructure. It is essential for IJs to maintain railroad track’s structural continuity while having an important role in track circuit design and implementation. The structural integrity and performance of IJs have been recognized as a key interest area by the railroads as a result of increasing average axle loads and train traffic. While there are many different designs offered by various manufacturers around the globe, the main approach utilized by heavy haul railroads in the US, Canada and many other countries has been to use adhesively bonded insulated joint bars between two rails. This approach offers the benefit of a composite assembly where the continuous bond between rails and bars offer a geometrically uninterrupted transfer of loads between rails and bars. The main components of a bonded IJ are joint bars, insulation material, adhesive, endpost, and bolts or other fasteners. This paper summarizes recent design improvements on these components. The main focus areas of the research are bar design, bar material selection, insulator and adhesive selection and using a novel endpost design for load transfer between two rails. Track support conditions’ impact on IJ performance has also been considered as a factor influencing IJ performance in track and incorporated in the study. The impact of insulation material selection on IJ performance is discussed. Finite element analysis was used extensively in the study where the analysis results were supported by laboratory and field testing. The results of the study indicate dynamic stresses in bonded IJs can be reduced nearly 40% in joint bars by a combination of design improvements on IJ components. Improved bar material properties are expected to lead to considerably reduced risk of bar fatigue failures in track.

Low Solar Absorption Coating for Reducing Rail Temperature

The feasibility of using low-solar-absorption coatings to reduce the temperature rise of rails in summer is investigated in this paper using numerical analysis. Finite element (FE) models were developed based on the theory of heat transfer for predicting temperature fields in the rail track structure. Field measurements of air temperature and rail temperature were used to verify the modeled temperatures. Analysis results show that the developed FE models provide reasonable predictions of rail temperature. The 3-D rail temperature field shows that rail temperature differs spatially in the natural environment, which indicates that the current average temperature models may not provide accurate prediction of peak rail temperature. The peak temperature was observed at the top of rail seated on the wood ties. The developed FE models were further used to analyze the influence of solar absorptivity and emissivity of coating materials on rail temperature. Decreasing the absorptivity and increasing the emissivity of rail surface may decrease the peak rail temperature at different levels. The effect of decreased absorptivity was found to be more significant. This indicates that when an engineered coating material is applied on rail side surfaces, the peak rail temperature can be decreased significantly, which provides an alternative solution to reduce rail buckling risk without decreasing train speed or increasing the laydown temperature of rail. The experimental investigation of the effect of low solar absorption coating on rail temperature is ongoing.

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.