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.

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Limiting harmful locomotive exhaust emissions is important to the Nation’s health and safety. The Environmental Protection Agency (EPA) has comprehensive gaseous exhaust emissions (or referred to as emissions hereto) testing requirements in place. All current tests are conducted on stationary locomotives. This paper discusses the development of an efficient stationary emissions measurement system that is compact, portable, easy to use, and applicable to onboard locomotives for in-use, over-the-road testing. More efficient locomotive emissions testing and better understanding of in-use emissions would be beneficial to all stakeholders. Sharma & Associates, Inc., (SA) adapted an off-the-shelf, portable, on-road, heavy-duty diesel truck emissions analyzer for locomotive use. This process included development of the necessary peripheral equipment and a computer program to take the raw emissions and report them as brake-specific emissions rates and duty cycle emissions. This paper describes the use of this system on a stationary locomotive. The system is currently being fitted and tested for over-the-road use. The measurement of particulate matter and smoke opacity were out of scope of the phase of the project that this paper is based on and not addressed hereto.

The Federal Railroad Administration has embarked on a pilot project to demonstrate the feasibility of using and linking defect detector systems for rail vehicles across North America. The goal of this project is to develop a national database that will enable the railroad industry to engage in predictive maintenance. These detectors measure equipment performance parameters such as the forces between the wheel and rails. The Integrated Railway Remote Information Service or InteRRIS™, an Internet-based system designed and developed by Transportation Technology Center, Inc. (TTCI), was used to aggregate, interrogate, and store data from field-deployed detector systems. TTCI is a wholly owned subsidiary of the Association of American Railroads (AAR). A key task of this program was the determination and implementation of appropriate access to a National Rail Corridor Vehicle Performance Database (VPD). The VPD can draw performance-based data from InteRRIS™ for the FRA and the railroads responsible for the safe operation of cars and locomotives as needed to enable effective performance-based safety monitoring. The VPD has been populated with data from a number of Truck Performance Detectors (TPD) and Wheel Impact Load Detectors (WILD™) in order to capture representative and geographically diverse traffic from freight, mixed freight/commuter/passenger lines, and hazardous materials lines. Both the AAR and FRA have a mutual interest in promoting the implementation of performance-based maintenance. It is hoped that this detector network and associated national database reduces the need for visual inspections on cars and locomotives, thereby focusing more efforts on preventive action and making repairs. This could greatly enhance the efficiency with which railroads make critical repairs in a timely manner. Such tools, with detector data in a central database, should they prove feasible, could eventually lead to the development of performance-based inspection standards.

Longitudinal dynamics influence several measures of train performance, including schedules and energy efficiency, stopping distances, run-in/run-out forces, etc. Therefore, an effective set of tools for studying longitudinal dynamics is essential to improving the safety and performance of train operations. Train Energy and Dynamics Simulator (TEDS) is a state-of-the-art software program designed and developed by the Federal Railroad Administration (FRA), for studying and simulating train safety and performance, and can be used for modeling train performance under a wide variety of equipment, track, and operating configurations [1]. Several case studies and real-world applications of TEDS, including the investigation of multiple train make-up and train handling related derailments, a study of train stopping distances, evaluations of the safety benefits of Electronically Controlled Pneumatic (ECP) brakes, Distributed Power operations, and a study of alternate train handling methodologies are described in this paper. These studies demonstrate the effectiveness of using the appropriate simulation tools to quantify and enhance a better understanding of train dynamics, and the resultant safety benefits.