Measurement of the Aerodynamic Pressures Produced by Passing Trains

This paper describes measurement of the aerodynamic pressures produced by a Bombardier High-Speed Non-Electric Locomotive (HSNEL) on an adjacent stationary double-stack freight car. Static pressures are measured on the near and far-side faces of the freight containers over a range of locomotive speeds from 60 to 130 mph. This data is also compared with the pressures predicted by computational fluid dynamics (CFD) simulations.

Mid-Life Structural Assessment of Transit Rail Cars at WMATA

The Washington Metropolitan Area Transit Authority (WMATA) contracted with Booz Allen Hamilton to conduct a non-destructive structural assessment of the 2000 and 3000 series rapid transit rail cars. The main goals of the assessment were to identify any significant changes that have occurred to key elements of the car body structure since their date of manufacture and to confirm that no significant and obvious structural deterioration or damage exists. The methodology behind selecting a small representative sample of cars is discussed as an introduction to this work. The paper then discusses the process by which several critical areas were selected for non-destructive inspection. One of the biggest challenges in successfully completing this project was not interfering with WMATA’s fleet operating requirements. The use of WMATA facilities had to be coordinated to create minimum interference with WMATA’s daily maintenance activities. Also, the inspection work had to be planned in such a way as to minimize the amount of vehicle component disassembly in order to return the vehicle to revenue service as soon as possible. The inspections produced valuable results regarding the construction and condition of these cars. The structural welds of the car appear to have performed satisfactorily through the operational life of the cars to date without any significant deterioration. Some corrosion was noted in the door opening areas of the cars, particularly at the door thresholds. The findings of this report will be used to target specific areas of the car during the upcoming mid-life rehabilitation project.

Remote Ride Quality Monitoring of Acela Train Set Performance

Federal Track Safety Standards require daily measurements of car body and truck accelerations on trains operating at speeds above 125-MPH. In compliance with this requirement, twelve high-speed Acela coaches, operating in the Northeast Corridor between Boston, MA, and Washington DC, have been equipped with remote monitoring systems. The systems provide continuous measurement of car body and truck motions, detect various acceleration events, tag them with GPS time and location information, and deliver the data to Central Processing Stations through wireless communications channels. The Central Processing Stations installed at the National Railroad Passenger Corporation (Amtrak) and ENSCO, Inc., headquarters provide email and pager notifications to designated Amtrak officers and also make the data available to them over secure Intranet and Internet connections. The overall architecture has multiple levels of protection and redundancy in order to ensure high reliability and availability of the service. The systems have been in continuous operation for over a year and provided a multitude of valuable information. Examples of system-reported acceleration events include events caused by track irregularities and train handling. The paper also describes some of the real-life operational scenarios and situations that arise when autonomous remote monitoring systems are used, including wireless communications coverage issues, GPS location pitfalls, and maintenance issues.

Air Dryers in Railway Service: History, Performance and Present Status

Pneumatic systems in railway applications are vulnerable to water condensation as a result of the cooling of compressed air. This water tends to cause corrosion, degrade lubricants and freeze in cold weather, causing malfunction in brake systems and other pneumatic devices. Prevailing practice for the control of condensation until the early 70’s consisted of cooling the compressed air followed by reduction in pressure to lower the relative humidity. These methods were less than perfect and frozen systems remained a major cause of train delays in cold climates and, in all climates, water continued to corrode devices and emulsify lubricants, increasing maintenance requirements. Regenerating desiccant type air dryers offered a solution. This paper deals with the history of air dryers in railway service, the technologies involved, and the broad significance to the industry.

Remote Condition Monitoring for Railway Point Machine

This paper presents the research work carried out at Oxford University on condition monitoring of railway point machines. The developed condition monitoring system includes a variety of sensors for acquiring trackside data related to different parameters. Key events to be logged include time stamping of points operation, opening and closing of case cover associated with a points machine, insertion and removal of a hand-crank, loss of supply current and the passage of a train. The system also has built-in Web functions. This allows a remote operator using Internet Explorer to observe the condition of the point machine at any time, while the acquired data can be downloaded automatically for offline analysis, providing more detailed information on the health condition of the monitored point machine. A short daily condition report message can also be sent to relevant staff via email. At last the experience are reported on the four trackside installed systems.

Multibody Simulation of a Freight Bogie With Friction Dampers

Freight bogies are often built using friction element instead of viscous dampers with great advantage regarding cost and manutenibility. On the other hand this technical choice leads to low performance of the vehicle. The aim of this work is to evaluate the behaviour of a Y25 freight bogie that is the most diffuse in Europe where friction dampers are used to reduce vertical and hunting vibrations. The purpose is also to improve a bi-dimensional model of friction damper and to test its numerical efficiency on a whole vehicle model in a multibody code.

Field Testing and Monitoring of Rolling Stock Under the New Federal Track and Equipment Regulations

In the past three years, the Federal Railroad Administration (FRA) has issued two significant new regulations covering the qualification and operation of passenger railroad equipment. The 1998 Track Safety Standards and 1999 Passenger Equipment Safety Standards provide comprehensive requirements for the qualification and operation of passenger equipment. Among many safety issues, these standards address the response of rolling stock at speed to track deviations, and the potential for derailment and/or injury to passengers. The principles contained in the Safety Standards are also used by FRA to evaluate safety performance of vehicles for operation at high cant deficiency for speeds less than 90 mph as part of FRA’s waiver process. This paper describes the types of static and dynamic tests and equipment that are required with respect to vehicle-track interaction to demonstrate compliance of new equipment with the Standards, and the technical fundamentals behind the requirements. Examples include the National Railroad Passenger Corporation’s (Amtrak’s) experiences in applying for waivers and qualifying new equipment under these regulations, particularly the high cant deficiency testing of the Talgo train in the Pacific Northwest, and the high-speed and high cant deficiency testing of Maryland Rail Commuter’s (MARC’s) MARC-III bi-level cars, Acela Express trainsets and Amtrak’s high-horsepower electric locomotives in the Northeast Corridor. In addition, technical data and procedures necessary to have existing equipment approved for operation at higher speed or cant deficiency are also described. This paper highlights nuances of the new regulations and common misinterpretations.

Development of a Computer Model for Prediction of Collision Response of a Railroad Passenger Car

The paper describes the development of a detailed finite element model that is capable of predicting the response of a rail passenger car to collision conditions. This model was developed to predict the car crush, the three-dimensional gross motions of the car, and the vertical, lateral, and longitudinal accelerations experienced by the car during collisions. The finite element model developed was for a Pioneer passenger coach car. This vehicle was used in a single car impact test. The model was then used to simulate the test and the results are compared to the test data.

Bearing Defect Detection Using On-Board Accelerometer Measurements

Vibration signatures of defective roller bearings on railroad freight cars were analyzed in an effort to develop an algorithm for detecting bearing defects. The effort is part of a project to develop an on-board condition monitoring system for freight trains. The Office of Research and Development of the Federal Railroad Administration (FRA) is sponsoring the project. The measurements were made at the Transportation Technology Center (TTC) in Pueblo, CO on July 26 – 29, 1999 during the Phase III Field Test of the Improved Wayside Freight Car Roller Bearing Inspection Research Program sponsored by FRA and the Association of American Railroads (AAR). Wheel sets with specific roller bearing defects were installed on a test train consisting of 8 freight cars designed to simulate revenue service. The consist also contained non-defective roller bearings. Accelerometers were installed on the inboard side of the bearing adapters to measure the vibration signatures during the test. Signatures of both defective and non-defective bearings were recorded. The data were recorded on Sony Digital Audio Tape (DAT) Recorders sampling at a rate of 48 K samples per second. We used both ordinary and envelope spectral analysis to analyze the data in an effort to detect features that could be related to known defects. The spectra of non-defective bearings show no remarkable features at bearing defect frequencies. In general, the ordinary spectra of defective bearings do not exhibit remarkable features at the bearing defect frequencies. In contrast, the envelope spectra of defective bearings contain a number of highly resolved spectral lines at these frequencies. In several cases the spectral lines could be related to specific bearing defects. Based on the analysis performed to date, the envelope spectrum technique provides a promising method for detecting defects in freight car roller bearings using an on-board condition monitoring system.