bluuebunny/crossref_metadata_2025 huggingface dataset:
USP8 Controls the Trafficking and Sorting of Lysosomal Enzymes
Authors: MacDonald Ewan , Urbé Sylvie , Clague Michael J.
Published: June 2014

The endosomal deubiquitylase USP8 has profound effects on endosomal morphology and organisation. Previous reports have proposed both positive (EGFR, MET) and negative roles in the down‐regulation of receptors (Frizzled, Smoothened). Here we report an additional influence of USP8 on the retromer‐dependent shuttling of ci‐M6PR between the sorting endosome and biosynthetic pathway. Depletion of USP8 leads to a steady state redistribution of ci‐M6PR from the Trans‐Golgi Network (TGN) to endosomal compartments. Consequently we observe a defect in sorting of lysosomal enzymes, evidenced by increased levels of unprocessed Cathepsin D, which is secreted into the medium. The normal distribution of receptor can be restored by expression of siRNA‐resistant USP8 but not by a catalytically inactive mutant or a truncated form, lacking a MIT domain required for endosomal localisation. We suggest that effects of USP8 depletion may reflect the loss of ESCRT‐0 components which associate with retromer components Vps35 and SNX1, whilst failure to efficiently deliver lysosomal enzymes may also contribute to the observed block in receptor tyrosine kinase degradation.
Numerical Analysis of a Size-Structured Population Model with a Dynamical Resource
Authors: Angulo Oscar , Lopez-Marcos J C , Lopez-Marcos M A
Published: June 2014

In this paper, we analyze the convergence of a second order numerical method for the approximation of a size-structured population model whose dependency on the environment is managed by the evolution of a vital resource. Optimal rate of convergence is derived. Numerical experiments are also reported to demonstrate the predicted accuracy of the scheme. Also, it is applied for the solution of a problem that describes the dynamics of a Daphnia magna population, paying attention to the unstable case.
On Nonlinear Dynamics of the STAT5a Signaling Protein
Authors: Nikolova Elena , Jordanov Ivan , Vitanov Nikolay K.
Published: June 2014

In this paper we model the dynamics of the cross talk between MEK/ERK and JAK/STAT signaling pathways by means of nonlinear ordinary differential equations. The considered system В of four ordinary differential equations is reduced to one ordinary differential equation, representing dynamics of the phosphorylated STAT5a signaling protein. We show that the diffusion together with the corresponding biochemical reactions is likely to play a critical role in governing the dynamical behavior of the considered signaling protein. В By the modified method of simplest equation to the described reaction-diffusion equation we obtain an analytical solution which explains drop and jump propagation of the STAT5a protein concentration.
Mathematical Modelling and Optimal Control of Anthracnose
Authors: Fotsa David , Houpa Elvis , Bekolle David , Thron Christopher , Ndoumbe Michel
Published: June 2014

In this paper we propose two nonlinear models for the control of anthracnose disease. The first one is an ordinary differential equation (ODE) model which represents the whithin host evolution of the disease. The second model includes spatial diffusion of the disease in a bounded domain О©. We show well formulation of those models checking existence of solutions for given initial conditions and positive invariance of positive cone. Considering a quadratic cost functional and applying maximum principle we construct a feedback optimal control for the EDO model which is evaluated through numerical simulations with scientific software ScilabВ®. For the diffusion model we establish under some conditions existence of unique optimal control with respect to a generalized version of cost functional mentioned before. We also provide a characterization for existing optimal control. Finally we discuss a family of nonlinear controlled systems.
On a Bivariate Poisson Negative Binomial Risk Process
Authors: Kostadinova Krasimira , Minkova Leda
Published: June 2014

In this paper we define a bivariate counting process as a compound Poisson process with bivariate negative binomial compounding distribution. We investigate some of its basic properties, recursion formulas and probability mass function. Then we consider a risk model in which the claim counting process is the defined bivariate Poisson negative binomial process. For the defined risk model we derive the distribution of the time to ruin in two cases and the corresponding Laplace transforms. We discuss in detail the particular case of exponentially distributed claims.
Risk Based Broken Rail Detection on Railways
Authors: Thurston David F.
Published: June 2014

There has been a long debate among train control professionals related to broken rail detection; where it is required and how it is achieved. Despite this ongoing discussion, there has been little research in terms of the actual practical application of new technology or risk mitigation approaches since conventional track circuits have been applied to detect broken rails.

This paper first looks at conventional broken rail detection as implemented with various track circuit types, then reviews the current research on alternate means of detection throughout the world.

The paper will then quantify a risk based approach utilizing existing technologies to mitigate the broken rail requirements currently mandated for higher speed rail systems in the United States. Further, the implications for train control systems for both transit and the general system of railroads will be examined.
Engineering Studies on Joint Bar Integrity: Part I — Field Surveys and Observed Failure Modes
Authors: Jeong David Y. , Bruzek Radim , Tajaddini Ali
Published: June 2014

This paper is the first of a two-part series describing a research project, sponsored by the Federal Railroad Administration (FRA), to study the structural integrity of joint bars. In Part I of this series, observations from field surveys conducted on revenue service track are presented. Automated and visual inspections of rail joints were conducted to identify defective joint bars. Detailed information and measurements were collected at various joint locations.

The survey team consisted of personnel from ENSCO, Inc. and Transportation Technology Center, Inc. (TTCI), working in cooperation with staff from participating railroads. Part II of this series describes the development of finite element analyses of jointed rail, which is being carried out by the Volpe National Transportation Systems Center (Volpe Center).
Assessment of Broken Rail Protection in Audio Frequency Track Circuits
Authors: Schaad Joseph W.
Published: June 2014

In addition to the vital function of train detection, a track circuit is also expected to provide an indication of a broken rail within its boundaries.

Ability to detect a broken rail in a double rail track circuit is a result of the failsafe design principle, which interrupts the flow of track signal current and drops the track relay in the presence of any credible component failure. The overall result of such an event is identical to that of track occupancy, which causes the associated signals to be set to the most restrictive aspect.

In the case of electrified territory, the ability to detect a broken rail may be compromised by the presence of crossbonds between parallel tracks. These additional connections, which are intended to minimize potential differences in the negative return system, also provide a sneak path for track signal current to flow from transmit to receive ends of the track circuit under broken rail conditions. In most cases involving 2 parallel tracks, application of a simple rule of thumb (described in this paper) regarding crossbond spacing and track circuit length is sufficient to ensure broken rail protection. In situations which are marginal, or where complex track work is involved, a more detailed analysis is necessary. Evaluation of the broken rail protection in such cases requires that the sneak path impedance be calculated and compared to the normal track circuit impedance. A formal method for this impedance calculation, based upon the classical circuit analysis techniques, is presented.

To completely characterize the behavior of the track circuit under broken rail conditions, the operational characteristics of the track circuit must also be considered. In this paper a digital jointless AF track circuit, operating in the 9.5–20.7 kHz range, is used as a basis for this discussion. The operational characteristics of the S-bond, O-bond, as well as the role of overdrive are considered in the context of broken rail (BR) protection.

The mathematical methods described for the simplified examples in this paper can readily be expanded to include any number of parallel tracks.
Ultrasonic Tomography for Rail Flaw Imaging
Authors: Phillips Robert , Lanza di Scalea Francesco , Nucera Claudio , Rizzo Piervincenzo , Al-Nazer Leith
Published: June 2014

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.
A Study on a Multiple Film Technique Utilized in Radiographic Examination for Steel Castings With Complicated Geometry
Authors: Ao Zhijun , Li Leon , Wei Zunfa
Published: June 2014

Castings on transit railcars often have complicated geometry. Varying thicknesses and limited space for shooting are difficult for radiographic testing of such castings. To reach the high-quality requirements of the density, accuracy, contrast, and sharpness of the films, a series of experiment were performed on one casting with complicated geometry to compare different results from different shooting methodologies.

Films with different ISO speeds are suitable for different wall thickness while their detection ranges overlap with each other. By adopting multiple film techniques, radiographic quality is enhanced when inspecting complicated castings geometries. The utilization of lead intensifying screen contributes to improve the image quality of the radiograph, so that the absorption of different sections is equalized and the prescribed quality level and density requirements are met. Latitude of film is improved by selecting appropriate voltage. Source-to-film distance is increased in order to minimize geometric unsharpness and ensure overall uniformity. Lead foil screens are utilized as a filter in front of films to absorb scattered radiation. In addition, back scatter radiation is reduced by placing lead plates behind the cassette. Large focal spot size is adopted. Short time of exposure is preferentially selected for the purpose of reducing the active time of scattered radiation. Moreover, the selection of other associated processing parameters helps to lessen the adverse effects caused by complicated casting geometries.

The results of these experiments show that the quantities of films and inspection cost can be reduced, efficiency of inspection can be improved; missing detection in complicated areas can be effectively avoided; the detection capability is increased and reliability of inspection results is ensured. In conclusion, the multiple film technique is a satisfactory methodology for radiographic testing of steel castings with complicated geometry.
Lateral Impact of Railroad Bridges With Hybrid Composite Beams: Finite Element Modeling and Preliminary Dynamic Behavior Study of HCB
Authors: Jing Yuan , Ma Z. John , Bennett Richard M. , Clarke David B.
Published: June 2014

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.
Applying Reliability and Availability Methods to Communication Based Train Control
Authors: Diemunsch Kenneth M. , Muthukrishnan Gopala
Published: June 2014

Reliability, Availability and Maintainability (RAM) engineering has been applied successfully for decades in many industries such as military electronics for aerospace [1] [2], nuclear power stations [3], and oil field services [4]. Several standards applying to train control have also been produced recently, for instance the IEEE recommended practice on Communication Based Train Control (CBTC) testing [5], the international standard for Reliability Availability Maintainability Safety (RAMS) in railway applications [6] and the European version [7]. Better Reliability and Availability (RA) involves a larger capital investment cost but results in lower maintenance cost and fewer system impacting delays. RAM engineering is used to define the optimal level of reliability and availability to minimize those two costs.

This paper introduces CBTC technology, including typical architectures of the subsystems which need to be modeled for the RA analysis. Basic RAM definitions and methods which can be applied to any system, including train control equipment, are presented. Then, the application of RA methods on CBTC system is discussed in terms of requirements, analysis, testing and methods to choose spare parts quantity.
Advances in Bonded Insulated Rail Joints to Improve Product Performance
Authors: Ciloglu Korhan , Frye Peter C. , Almes Scott , Shue Sidney
Published: June 2014

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.
Analysis and Development of Performance-Based Requirements for Railroad Tank Cars
Authors: Kirkpatrick Steven W. , MacNeill Robert A. , Gonzalez Francisco
Published: June 2014

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Ultimately, the results of this work will be used by the Government regulatory agencies in the United States and Canada to establish performance-based testing requirements and to develop methods to evaluate the crashworthiness and structural integrity of different tank car designs.

This paper describes analyses of current impact testing requirements and impact test methodologies using detailed finite element analyses (FEA). The results of these analyses are used to identify characteristics of the test methodologies that are desirable or undesirable for the test requirements in future tank car safety regulations.
Rail Temperature Prediction Model and Heat Slow Order Management
Authors: Bruzek Radim , Biess Larry , Kreisel Leopold , Al-Nazer Leith
Published: June 2014

Track buckling due to excessive rail temperature may cause derailments with serious consequences. To minimize the risk of derailments, slow orders are typically issued on sections of track in areas where an elevated rail temperature is expected and risk of track buckling is increased. While slow orders are an important preventive safety measure, they are costly as they disrupt timetables and can affect time-sensitive shipments. Optimizing the slow order management process would result in significant cost saving for the railroads.

The Federal Railroad Administration’s (FRA’s) Office of Research and Development has sponsored the development of a model for predicting rail temperatures using real time weather forecast data and predefined track parameters and a web-based system for providing resulting information to operators.

In cooperation with CSX Transportation (CSX) and FRA, ENSCO Inc. conducted a comprehensive model verification study by comparing actual rail temperatures measured by wayside sensors installed at 23 measurement sites located across the CSX network with the rail temperatures predicted by the model based on weather forecast data over the course of spring and summer 2012. In addition to the correlation analysis, detection theory was used to evaluate the model’s ability to correctly identify instances when rail temperatures are elevated above a wide range of thresholds. Detection theory provides a good way of comparing the performance of the model to the performance of the current industry practice of estimating rail temperature based on constant offsets above predicted daily peak ambient air temperatures.

As a next step in order to quantify the impact of implementation of the model on CSX operations, heat slow orders issued by CSX in 2012 on 10 selected subdivisions were compared to theoretical heat slow orders generated by the model.

The paper outlines the analysis approach together with correlation, detection theory and slow order comparison results. The analysis results along with investigation of past heat related track buckle derailments indicate that the railroad would benefit from adopting the rail temperature prediction model along with flexible rail temperature thresholds. The implementation of the model will have a positive impact on safety by allowing for issuing of advance heat slow orders in more accurate, effective and targeted way.
Coupling the “Sandwich” Track Model to a Commercial Dynamic Vehicle Model
Authors: Stigers Shelby , Gao Yin , Huang Hai
Published: June 2014

Most commercial vehicle dynamic modeling programs do not have, or have a very limited, track component. Today, most track dynamic models do not have a detailed vehicle model either. Assumptions have to be made to simulate the vehicle and track performances when using those programs. For instance, a predefined wheel-rail contact force is normally assumed as the input for both vehicle and track models. This research aims to integrate a previously developed “Sandwich” dynamic track model to a detailed vehicle model in a commercially available program so that a vehicle-track dynamic interaction can be realistically simulated. Case studies will be presented to demonstrate the coupling effect and the results will help us better understand the vehicle and track behavior under different riding conditions.
Analysis of the Relationship Between Rail Seat Load Distribution and Rail Seat Deterioration in Concrete Crossties
Authors: Greve Matthew , Dersch Marcus S. , Edwards J. Riley , Barkan Christopher P. L. , Mediavilla Jose , Wilson Brent M.
Published: June 2014

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.
Improving Resiliency in Communications Systems in Public Transit After Severe Weather Events
Authors: Fitzmaurice Michael
Published: June 2014

Subway stations and tunnels typically contain many different communications systems used by a transit agency to support the safe movement of passenger trains. When these stations and tunnels are flooded with water from excessive rains or hurricane related storm surges the resulting damage to these systems, devices and associated cabling can render them ineffective or completely inoperable. This in turn leads to costly repairs and replacement programs entailing lengthy service disruptions.

This paper will look at how the repair and replacement of communications systems damaged by the exposure to accumulated rain and salt water from a storm surge can be implemented so as to improve the overall system’s resiliency to future severe weather events.
Surface Wave Testing for Characterization of Ballast and Foundation Layers
Authors: Azari Hoda , Yuan Deren , Nazarian Soheil , Stark Timothy D. , Ho Carlton L. , Dehlin Thomas J.
Published: June 2014

The subsurface structure of a track system consists of ballast bed and soil foundation. Ballast fouling due to degradation and infiltration of other materials from the ballast surface and the foundation has been a common problem with rail track performance. The efficiency of a track system decreases with time due to ballast fouling and/or loss of the shear strength of foundation soil. Monitoring and identifying the changes in mechanical properties of ballast and foundation soil in a track system are essential to schedule and predict maintenance costs and to improve safety. Unlike qualitative measurements with the electromagnetic waves, for example, Ground Penetrating Radar, wave velocity measurements provide an opportunity to estimate the distribution of rail system stiffness with depth that can be directly in design.
Analysis of Trends in Commuter Rail Energy Efficiency
Authors: DiDomenico Giovanni C. , Dick C. Tyler
Published: June 2014

Commuter rail systems are widely regarded as an effective transportation alternative to reduce energy consumption and emissions in large urban areas. Use of commuter rail systems in the United States is on the rise, with annual ridership increasing by 28 percent between 1997 and 2007 [1]. With growing concerns about the sustainability and environmental impacts of transportation, modal energy efficiency is increasingly considered amongst the metrics to evaluate the benefits and costs of transportation systems and justify future investment. To gauge the relative long-term efficiency trends for rail as an urban transportation mode, this study analyzes historic trends in energy efficiency metrics for US commuter rail systems. Commuter rail systems receiving, or benefiting from, Federal Transit Administration (FTA) grants are required to report operations and energy consumption data on an annual basis to the National Transit Database (NTD). NTD data on energy consumption, operations, and services supplied from 1997 to 2011 are analyzed to determine historic trends in various energy efficiency metrics for the commuter rail mode as a whole. The data analysis and comparison of the results with the highway mode is complicated by the use of electric traction by some commuter rail operators. These operators report energy consumption in purchased electricity (kWh) instead of gallons of liquid fuel. The different approaches that can be employed to compare these two forms of propulsion and their intrinsic efficiencies and energy sources are discussed. Energy efficiency of each commuter rail system and its relationship to individual system characteristics during the study period are also analyzed. Finally, case studies of historic energy efficiency of individual commuter rail systems with longer operating histories and reporting data over the majority of the study period are contrasted against more recent start-up systems. While many systems outperform the energy efficiency of a typical light-duty vehicle, there are others that, due to a variety of system parameters and characteristics, fail to achieve a load factor great enough to make them more attractive than the highway mode on a gross average level. It is hoped that highlighting trends and variation in commuter rail energy efficiency will allow policymakers to make more informed decisions regarding the environmental benefits of rail as an urban transportation mode.
Dual-Mode Propulsion Extends Range of High Speed Rail
Authors: Scales Brian T.
Published: June 2014

Dual-mode propulsion in the form of electro-diesel and battery-electric locomotives is an established concept. Locomotives using these technologies have been in service for many years to provide a ‘last-mile’ capability for freight trains and traction capability when electric power is not available due to system failure or intentionally during engineering work on the infrastructure. In recent times, dual-mode propulsion has extended the range of commuter trains with the introduction of electro-diesel locomotives that operate with third-rail or OHL electric power, or with diesel prime mover. In similar fashion, the range of high speed trains, capable of speeds of 110 mph or greater, can be extended beyond the OHL by adopting dual-mode propulsion. There are three circumstances where dual-mode propulsion of high speed trains is appropriate. The first case is where it is desired to extend high speed rail service now beyond the existing OHL territory in an interim stage while OHL equipment is installed on the route. The second case involves the extension of high speed rail service over an existing route where it not feasible to install OHL equipment. A typical example of the second case is where most of the operation is over an electrified line and the extension is a relatively small proportion of the total trip, possibly involving running over a line that also carries freight trains. The third case is the commencement of high speed rail service on an established line that is not electrified while the line is electrified progressively or completely new electrified line is being constructed. The Paper describes the conceptual design of a dual-mode high speed train that has the capability of operating in electric mode up to 186 mph and in diesel mode up to 110 mph. The train follows contemporary European high speed EMU practice for the electric mode aspect, with the driving cars replaced by driving power tenders (mobile traction power houses). The power tenders input electrical power to the EMU train at the direct current link in the propulsion system. Hotel and auxiliary power is provided by diesel generators mounted underfloor on two EMU cars. For changeover to all-electric propulsion, the power tenders are replaced by driving trailers, which increases the seating capacity of the train. The diesel generator sets are retained in the all-electric mode to provide hotel and auxiliary power and limited input traction power for get-u-home capability in the event of failure of the OHL system.
Secure Communication-Based Train Control: Performance Evaluation of a Design Framework
Authors: Aziminejad Arash , Seckin Mustafa
Published: June 2014

Railroads are increasingly using Communication-Based Train Control (CBTC) technology to improve service capacity and operating efficiency. CBTC is a mission-critical system under which train monitoring and train control are integrated into a single unified system through data links between vehicles, central processors, and wayside equipment. Radio over fiber technology provides a flexible and efficient solution for the Data Communication System (DCS) which needs to ensure integrity and reliability of message delivery in a transparent manner for the train control functions.

A Security Device (SD) is defined as a network entity located between the railroad administration’s (the customer) trusted wired network and the non-trusted portion of the DCS network including the radio-based segment, which runs on a customized piece of hardware with a secure operating system and provides secure gateway functionality. This paper puts forward a network architecture and SD software platform design which meets the requirements of a typical CBTC system. The IPSEC protocol used by the SD for data protection renders authentication service through X.509 certificates. A network setup is put together as the proof-of-concept for the presented design proposal and performance assessment is conducted through experimental studies.
Low Solar Absorption Coating for Reducing Rail Temperature
Authors: Wang Hao , Chen Jiaqi , Balaguru P. N. , Al-Nazer Leith
Published: June 2014

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.
Special Pole Design for Station Reconstruction
Authors: White Paul F. , Sexton Christine A. , Erickson Robert
Published: June 2014

This paper presents the special design and construction methods that were employed for suspension of the Overhead Contact System (OCS) at the Orient Heights Station of the Massachusetts Bay Transportation Authority, Boston, Massachusetts during rebuilding of the station. Existing catenary wires and supports were attached to the building prior to demolition, but had to be removed for demolition of the building. Tight clearances and cable routing along the building obstructed normal pole installations and span wire removals, but the design team devised a method for span wire/cantilever attachments with construction that provided clearances. This creative engineering approach allowed a temporary, yet permanent, support of the OCS, provided adequate clearance for heavy rail rapid transit trains and did not impact regular passenger service. The paper will also highlight the special pole attachments, the changeover from existing to temporary and then to permanent, and the engineering methods used to insure compliance with the National Electrical Safety Code (NESC) and the American Institute of Steel Construction (AISC).
Siding Spacing and the Incremental Capacity of the Transition From Single to Double Track
Authors: Atanassov Ivan , Dick C. Tyler , Barkan Christopher P. L.
Published: June 2014

The North American freight railroad network is projected to experience rising transportation demand in the coming decades, leading to increased congestion along many rail corridors. Increased interest in expanded passenger service on shared rail corridors will also create additional capacity demand. However, the nation’s rail lines are still predominantly single track with passing sidings, making double track installation a vital capacity upgrade measure to sustain future volumes. Since increasing capacity through double track installation requires significant capital investment, the second main track must be allocated along a line in an optimal manner to provide maximum return on investment. An approach of investing in the least costly segments first may yield good results, but only if the benefits for each segment are equal. This research seeks to identify if the benefit of double track varies between bottleneck segments, and if there are compounding benefits of double track between adjacent passing sidings. Previous research has explored the allocation of double track on an idealized line with evenly spaced passing sidings. Due to numerous physical and engineering constraints, existing lines often exhibit a mixture of siding spacing with single-track bottleneck sections of varying length. To investigate the incremental capacity of adding double-track segments to a route with variable siding spacing, several build-out strategies are tested on a representative subdivision under random, mixed freight and passenger traffic via Rail Traffic Controller simulation software. The presented results highlight the most effective method, based on train delay, of incremental single to double track expansion and the potential differences in benefit between strategies. The linear delay reduction characteristics of single-to-double track mainlines vary based on the initial spatial arrangement of passing sidings and amount of second main track installed. These results further the understanding of relationships between infrastructure location and freight delay, thereby serving as a guideline for the sustainable expansion of existing rail corridors in anticipation of future demands. While railroads must consider many factors in selecting capital expansion projects, these guidelines can streamline the decision process by helping to quickly identify the projects with the most potential for more detailed engineering evaluation. The methodology presented can eventually be incorporated into analyzing the progressions from double to triple track lines.
Vertical Load Path Under Static and Dynamic Loads in Concrete Crosstie and Fastening Systems
Authors: Manda Kartik R. , Dersch Marcus , Kernes Ryan , Edwards Riley J. , Lange David A.
Published: June 2014

An improved understanding of the vertical load path is necessary for improving the design methodology for concrete crossties and fastening systems. This study focuses on how the stiffness, geometry, and interface characteristics of system components affect the flow of forces in the vertical direction. An extensive field test program was undertaken to measure various forces, strains, displacements and rail seat pressures. A Track Loading Vehicle (TLV) was used to apply well-calibrated static loads. The TLV at slow speeds and moving freight and passenger consists at higher speeds were used to apply dynamic loads. Part of the analysis includes comparison of the static loads and the observed dynamic loads as a result of the trains passing over the test section at different speeds. This comparison helps define a dynamic loading factor that is needed for guiding design of the system. This study also focuses on understanding how the stiffness of the components in the system affects the flow of forces in the vertical direction. The study identifies that the stiffness of the support (ballast) underneath the crossties is crucial in determining the flow of forces. The advances made by this study provide insight into the loading demands on each component in the system, and will lead to improvements in design.
Gauging of Concrete Crossties to Investigate Load Path in Laboratory and Field Testing
Authors: Wei Sihang , Kuchma Daniel A. , Edwards J. Riley , Dersch Marcus S. , Kernes Ryan G.
Published: June 2014

To meet the demands of increasing freight axle loads and cumulative gross tonnages, as well as high-speed passenger rail development in North America, the performance and service life of concrete railway crossties must be improved. As a part of a study funded by the Federal Railroad Administration (FRA) aimed at improving concrete crossties and fastening systems, laboratory experimentation was performed at the Advanced Transportation Research Engineering Laboratory by researchers from the University of Illinois at Urbana-Champaign. This paper focuses on the behavior of concrete cross-ties as well as characterizing and quantifying the loads transmitted from the wheel/rail interface through the fastening system to the tie in the vertical direction. Concrete embedment strain gauges were cast below rail seat to create a “load cell” to measure the rail seat vertical load. Laboratory instrumentation efforts have been done to calibrate this vertical “load cell”. To understand the rail seat load and load path in the field, experimentation was performed at the Transportation Technology Center (TTC) in Pueblo, both static loading which were applied by TTC’s Track Loading Vehicle and dynamic loading due to real wheel-rail interaction were discussed. Concrete cross-tie bending behavior was also investigated through the use of strain gauges applied in the longitudinal axis of the crossties in both laboratory and field experiments. Results from these findings will be utilized to aid in the recommendations for the mechanistic design of various components within the fastening system.
Advancing the Science of Yard Design and Operations With the CSX Hump Yard Simulation System
Authors: Dick C. Tyler , Dirnberger Jeremiah R.
Published: June 2014

The Class 1 railroads in North America have made substantial investments in mainline and intermodal terminal capacity during the past two decades to meet growing traffic demand. Investments to increase hump classification yard capacity have been less frequent, with a handful of yard projects in the late 1990s and the last major round of new hump yards constructed in the late 1970s. At this time of large investment in yards, much basic research was conducted on hump yard design and performance, while more recent studies have looked at applying lean process improvement and block optimization to hump yards. Due to the complexity of the problem, these studies tend to focus on one aspect of the terminal capacity question at a time, leaving the industry without a comprehensive understanding of the fundamental interrelationships between all aspects of hump yard performance in terms of volume, utilization and reliability. Without such an understanding, the industry cannot make fully informed decisions regarding the hump yard capacity investments that are now the subject of renewed interest due to the combination of carload market shifts, traffic growth facilitated by mainline capacity investment, and aging congested yard infrastructure. To address this need, CSX Transportation developed its Hump Yard Simulation System (HYSS). HYSS considers the operations, process and infrastructure parameters of a hump yard, and their interactions, in a single simulation to evaluate terminal performance. In the HYSS graphical environment, users can evaluate any combination of changes to terminal operating plans, yard processes and infrastructure layout. While developed to address specific business needs, as a simulation tool, HYSS has the potential to investigate the fundamental relationships governing hump yard operations in a manner not possible before. To realize this potential, CSX is partnering with the Rail Transportation and Engineering Center (RailTEC) at the University of Illinois to deploy HYSS in an academic research environment. Design of experiments techniques will be used to conduct a series of HYSS simulations to quantify the interaction between hump yard throughput, number of blocks and the delivered level of service at the terminal, and the sensitivity of this relationship to other operational and infrastructure variables. This paper will introduce HYSS as a research tool, examine how its various outputs are used to quantify terminal performance, and describe the planned research program aimed at advancing the science of hump yard design and operations.
Studies on the Accuracy Stability and Efficiency of a New Time Integration Scheme for Ballast Modeling Using the Discrete Element Method
Authors: Mathews G. F. , Mullen R. L. , Rizos D. C.
Published: June 2014

This paper presents the development of a semi-implicit time integration scheme, originally developed for structural dynamics in the 1970’s, and its implementation for use in Discrete Element Methods (DEM) for rigid particle interaction, and interaction of elastic bodies that are modeled as a cluster of rigid interconnected particles. The method is developed in view of ballast modeling that accounts for the flexibility of aggregates and the arbitrary shape and size of granules. The proposed scheme does not require any matrix inversions and is expressed in an incremental form making it appropriate for non-linear problems. The proposed method focuses on improving the efficiency, stability and accuracy of the solutions, as compared to current practice. A critical discussion of the findings of the studies is presented. Extended verification and assessment studies demonstrate that the proposed algorithm is unconditionally stable and accurate even for large time step sizes. It is demonstrated that the proposed method is at least as computationally efficient as the Central Difference Method. Guidelines for the implementation of the method to ballast modeling are discussed.
“Going Viral”: The Impact of Forced Crowdsourcing on Coaching Evaluation Procedures
Authors: Bass Jordan R. , Vermillion Mark , Putz Paul
Published: June 2014

In this paper, we examine the role of forced crowdsourcing in coaching evaluation and assessment systems. In previous conceptualizations, crowdsourcing (Howe, 2006) is an organization-controlled process where the opinion of the general public is used for organizational good. However, in sport, and particularly coaching, this is not always the case. Further, we detail the role of viral content in increasing public pressure during the monitoring, enforcing, and ultimately changing of organizational actions. Examples of American coaching scandals in sport were used to illustrate these concepts. From Woody Hayes to Bob Knight to Mike Rice, coaching scandals have captivated the public at large and forced administrators to weigh the public opinion against their own organizational morals and best practices. Finally, we argue organizations are often driven to act due to forced crowdsourced opinions. In all, increased forced crowdsourcing has fundamentally changed the previous insular dynamics of sporting organizations through increased awareness of coaching practices and the promotion of accountability among administrators for the actions of the coaches in their program.