Variable Directivity Acoustical Warning Device (AWD) as an Optimized Locomotive Horn

It is estimated that up to 9.3 million people may be impacted by locomotive horn noise and up to 4.6 million of those may be severely impacted.1 In 2009, there were over 1,900 incidents, over 700 injuries, and over 240 fatalities at highway-rail grade crossings.2 Approximately 4,000 times per year, a train and highway vehicle collide at one of over 262,000 public and private highway-rail grade crossings in the United States. Compared to a collision between two highway vehicles, a collision with a train is eleven times more likely to result in a fatality, and five and a half times more likely to result in a disabling injury. Approximately half of all collisions occur at grade crossings that are not fully equipped with warning devices. Some of the drivers involved in these collisions may have been unaware of the approaching train.3 The National Academy of Engineering Committee on Technology for a Quieter America has indicated that the public would benefit if a train horn was more directional and has recommended that research and development be undertaken to better understand the effects on safety, with benefits to the public.4 As a part of an ongoing Federal Railroad Administration (FRA)-sponsored research and development effort, the authors have developed an Acoustical Warning Device (AWD) prototype with an overall goal of maximizing safety at a grade crossing and minimizing environmental noise pollution (at the wayside and in the cabin of a locomotive in reducing railroad worker occupational hazard noise exposure). An initial prototype was created that consisted of one acoustical element. An advanced prototype is currently being developed with three acoustical elements to provide variable directivity and steering capabilities through beamforming. A digitized horn signal has been created based on characteristics from an analog air-pressure locomotive horn. The initial AWD prototype has been analyzed for detectability and noise impact area and the directivity pattern of its sound emissions have been tested. The expected performance of the advanced three-unit prototype has been evaluated based on the test results of the initial prototype and acoustic simulation modeling. During development of the initial AW D prototype, spectrograms, polar directivity plots, frequency response plots, 1/3-octave band plots, and LAeq measurements of the AWD propagation were analyzed to ensure proper functionality of the AWD, in accordance with FRA and QinetiQ North America’s (QNA) specifications. Based on acoustic simulation modeling, the advanced AWD prototype is expected to generate sound up to 110 dBA at 100 feet forward of the locomotive. The AWD prototype is expected to improve detectability and reduced environmental noise exposure to the community and locomotive cabin.

Duty Cycle and Transport Phenomenon Analysis of Battery Storage System for Hybrid Locomotive Application

The interest for developing hybrid electric locomotives consisting of diesel engine, regenerative braking and battery storage is growing due to increased demand and cost of diesel oil, uncertainty in the steady supply of oil, and increased standards for reduced emissions. Electrical energy is lost from electric locomotives in the form of heat during dynamic braking. Routing this energy using a regenerative braking system into battery stacks can improve the overall efficiency as it can be used later to provide traction force during acceleration. Objective of this study is to perform a feasibility analysis of modes of regenerating the energy developed in the braking and storing the energy in an electric battery storage system for use in railroad locomotive applications. Various road locomotive duty cycles, charge and discharge rates, and environmental conditions have been considered as this is expected to substantially influence the optimal performance and safety of the battery as well as the potential fuel savings that could be realized using a hybrid design. A computational algorithm is developed to determine the amount of energy that can be obtained from regenerative breaking during the run of locomotive and can be stored back into the stack of battery, which can be coupled with diesel engine to save additional consumption of fuel. A combined electrochemical and thermal simulation analysis of several battery configurations using multiphysics simulation code has also been performed in order to understand the thermal management and cooling requirements of the batteries subject to the charging and discharging requirements of a locomotive engine. Such an analysis assists in addressing the key issue of operating the battery at an maximum efficiency level while dissipating any excessive heat generated during the operation, and maintaining the battery at a desired temperature range using a cooling scheme.

Near-Race Ultrasonic Inspection of Tapered Roller Bearing Components for Non-Metallic Defects

Bearing steel cleanliness is directly linked to failures caused by the interaction of subsurface defects and rolling contact fatigue (RCF). Optical analysis of as-received steel coupled with ultrasonic inspection on finished components minimizes the occurrence of defects in the near race. While useful as a preventative measure, these methods do not ensure that critical areas of components subjected to RCF are free of defects that act as stress concentrators and contribute to premature failure. This presentation provides a brief summary of the current technology and standards utilized in the industry. The deficiencies of the current methods for the particular case at hand are identified and a surface wave scanning method is introduced. The development and production of reference parts for this type of scanning are then discussed. The production method entails both traditional electro-discharge machining (EDM) and femtosecond laser machining (FLM) on finished bearing components such that the reference part microstructure resembles that of a finished part. Experimental results utilizing surface wave scanning are given for two types of assembly-ready bearing components that are then subjected to realistic service loads and mileage to the point of failure. The results of the service life simulations are then correlated with surface wave scanning results and are shown to be in good agreement. This work is anticipated to impact any field in which components are subjected to RCF.

Infrastructure Data Management Systems Driven by Commercial Need: One Company’s Experience

The high cost of railroad infrastructure maintenance, compared to the relatively low cost and growing capability of systems to assess infrastructure condition, offers significant potential for cost saving through improved data management systems. This paper looks at one company’s experience of systems in Europe and focuses particularly on the commercial value that can be delivered — other company’s systems are of course also available. Balfour Beatty Rail (BBR) is one of the world’s largest rail engineering and services providers and a significant part of our business involves Asset Management in its broadest sense. BBR’s hands-on experience as a builder and maintainer of railways informs our understanding of what data is helpful to ensure safety and optimize maintenance. Many of our systems have evolved though our own needs in railway maintenance and all are very commercially focused. This paper looks at some of the commercial drivers for these systems and draws on experience from a number of applications in Europe to highlight key areas of benefit. The paper begins with the high level commercial case for data and its effective use, looking at the opportunity for cost savings in asset management. It then looks at the information required to deliver specific types of benefit. Experience with a new system for London Underground to maximize the use of their limited maintenance windows is described. The implications of the UK’s penalty regime for train delays is then discussed, showing how it has driven investment in signaling monitoring resulting in reliability and availability improvement. Condition visibility is an essential prerequisite for effective planning and root cause analysis. For track, subject to many simultaneous degradation modes, location-centered visualisation software is providing users a clearer view of all relevant parameters. By presenting measurements from many different sources to provide a unified view with a location accuracy to within one tie, better targeted and cost-effective maintenance can be undertaken. Software developed by German subsidiary Schreck-Mieves takes a new approach to data management during visual inspections. Initially developed exclusively for their own use, the system aims to quantify a manual inspection. Information is checked for errors and completeness and recording is ergonomically designed to minimize inspection time. Results are combined into an overall evaluation based on a new KAV® wear margin parameter and can be “rolled up” to cover all or part of the network. Finally the paper describes how the UK’s 150-year-old infrastructure has necessitated a different approach to gauging to maximize space. Through infrastructure data management systems and a more analytic approach it is possible to undertake calculations that estimate “true” clearances. This frees up available space which can be used to increase vehicle capacity or save money, with a recent example showing savings of up to $35m made over a 150mile route upgrade, reducing the scope or works by up to a third.

Train Energy and Dynamics Simulator (TEDS): A State-of-the-Art Longitudinal Train Dynamics Simulator

Train safety and operational efficiency are enhanced by the ability to understand the behavior of trains under varying conditions. Under the direction of the Federal Railroad Administration (FRA), a longitudinal train dynamics and operation simulation software — Train Energy and Dynamics Simulator (TEDS) — has been developed. TEDS is capable of modeling modern train operations and equipment, and is an effective tool for studying train operations safety and performance as affected by equipment, train makeup, train handling, track conditions, operating practices and environmental conditions. TEDS simulates the dynamics of longitudinal train action and incorporates the dynamic effects of various different types of draft gears and end-of-car cushioning units including mismatched devices coupled together, the transient response of locomotive tractive and dynamic braking effort, as well as a fluid dynamic representation of the air brake system with the capability to model conventional pneumatic and ECP brake systems. The capabilities of TEDS are described and demonstrated with several examples. The validation effort undertaken is described at both the component and system level. Comparisons of TEDS simulations of impact tests with the test results are shown to verify the draft gear and end-of-car cushioning unit models. The air brake model predictions are verified by comparing brake rack test results to TEDS simulations of braking behavior.

Liquefied Natural Gas (LNG) as a Freight Railroad Fuel: Perspective From a Western U.S. Railroad

The use of liquefied natural gas (LNG) as a line-haul locomotive fuel is not a new idea, despite recent publicity, with previous work stretching back into the 1980s. Intense publicity has been given to recent announcements about developing dual-fuel locomotive engines which can burn natural gas as the primary fuel, using diesel fuel only as a pilot fuel for gas ignition. However, developing a locomotive engine capable of using gaseous fuel may prove to be only one of five major challenges to widespread adoption of LNG as a freight railroad fuel: 1. Dual-fuel line-haul locomotives with engines which can use natural gas fuel must be developed and made available for use. 2. Natural gas fuel must be made available to dual-fuel locomotives, either onboard the locomotive itself or by using LNG tenders coupled to the locomotives. 3. LNG must be stored and available for refueling dual-fuel locomotives or their tenders at logical locations along railroad corridors where such locomotives are to be used. 4. Natural gas (from gas fields or pipelines) must be available along with liquefaction plants to convert the gas into cryogenic LNG fuel. 5. The safe operation of trains and locomotives, and safe maintenance of rolling stock, is paramount and cannot be compromised (nor should the efficiency of the rail system) should dual-fuel locomotives and LNG tenders supplant or replace conventional diesel-fueled locomotives. For LNG to become an effective large-scale freight railroad fuel, all five factors must be managed jointly and treated as a 5-legged technology system. If any one of the five “technology legs” is weak or improperly developed, the entire LNG-based system may be unsuitable in the freight railroad environment.

Lading Effects on Tank Car Impact Response

Tank car design requirements and tank car safety research both evaluate impact conditions for a fluid filled tank. For the test conditions, the fluid is typically water or water based slurry that has an appropriate density to represent a specific lading. The pressure is commonly applied to the tank using compressed air. In analyses, the effects of the fluid are often included using computational simplifications such as adding the weight of the fluid lading to the tank mass and adding a constant internal pressure to the tank. For specific impact scenarios the effects of these modeling approximations have been analyzed to assess the magnitude of the effects on impact and puncture behavior. This paper describes analyses performed to evaluate the effects of the lading on the impact and puncture behavior of tank cars. The lading is explicitly modeled in various impact conditions to assess the behavior of the lading and the effect of modeling approximations on the dynamic response. In addition, the effects of the internal pressure and outage volume of various commodities on the puncture behavior are also analyzed.

Wheel-Rail Contact Characteristics on a Tangent Track Vs a Roller Rig

This study derives explicit analytical expressions for comparing contact patch dimensions and Kalker’s coefficients for a wheel moving on a roller and compares the results with a tangent track arrangement. The expressions suggest that full size roller rig will underpredict Kalker’s traction coefficients (creepage forces per unit creepage) by a factor that depends on the roller radius. Studying rail-wheel contact mechanics and dynamics in the field conditions can prove to be challenging due to the difficulties in adequately controlling the test conditions that can significantly affect the results, such as track irregularities, rail surface condition, etc. Roller rigs can prove to be a useful tool for such studies. One, however, must be careful when interpreting roller rig test results because of the differences in wheel-rail contact mechanics and dynamics between the track and the roller. The findings of this study, which are consistent with other studies’ conclusions, will allow researchers to relate results with field testing.

Development of Analytical Models for Railroad Tank Car Impact and Puncture Behaviors

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture safety. However, the performance of the detailed analyses or full scale testing can require significant computer or financial resources to evaluate a wide range of impact scenarios. This paper describes the development of analytical models that can predict the impact and puncture behavior of a pressurized railroad tank car. The methodology applied is to first develop a model that can predict the force-deflection behavior obtained from a general impact at any point on the tank. Separately, a characteristic puncture force is determined as a function of the tank geometry, impactor geometry, and impact conditions. Combined, these models can be applied to predict the impact and puncture behavior of the tank.

Next Generation Locomotive Cab

This paper discusses the development of a user-centered control stand for the Federal Railroad Administration’s (FRA) Next Generation Locomotive Cab (NGLC) demonstration program. A “modified” Association of American Railroads (AAR) 105 side-mounted control stand was used as a starting point to facilitate bidirectional locomotive operation. Researchers applied a variety of qualitative human factor methods, including literature review, naturalistic observation, computer modeling, and heuristic evaluation, to design the improved control stand. The final design included a decluttered side control stand, a short desktop with three-panel front touchscreen displays that can accommodate and integrate current and future locomotive train technologies, and an overhead ceiling panel that replaces, in part, controls and displays traditionally located behind the engineer on the back wall. A mockup of the revised control stand design was fabricated as part of this program to demonstrate the human factors and ergonomic improvements. Researchers conducted structured interviews with locomotive engineers to validate the user-centered design approach. The engineers engaged in interactive scenarios that assessed the functionality of the workspace. The usability results provided the opportunity to improve upon the initial NGLC user-centered design. Changes included minor relocation of controls because they were in the reach path of other controls. Certain frequently accessed controls required relocation to more accessible locations. The LCD displays were redesigned with respect to information groupings and visibility issues. Feedback revealed that the transition from mechanical operations to electronic operations will result in the loss of auditory cues inherent in mechanical operations. The researchers suggest simulating auditory cues to promote personnel transition from mechanical to electronic operations. The results of this usability assessment identify the opportunity for future R&D cab integration efforts and demonstrate the importance of user-centered design and usability assessment in these efforts.