Nondestructive flaw testing of rails in track by induction methods is described and compared with ultrasonic methods. Relative strengths and weaknesses of induction testing are listed. Results taken from concurrent induction and ultrasonic testing are given which demonstrate the complementary nature of the two methods.

Effectively monitoring the rate of rail wear is a cost effective solution for the planning of maintenance and for the projection of rail requirements. Typically, portable measurement instruments are used to measure the rail profile and make dimensional measurements. This process was time consuming and inefficient due to the fact that manpower had to travel to remote locations and perform manual measurements whether rail wear existed or not. In addition, this method was subjected to error introduced by the user and by the limited number of samples that can be collected. KLD Labs, Inc. conceived the idea for an automated rail inspection system 15 years ago using an optical technique. This technique was developed into a measurement system called the Optical Rail Inspection and Analysis (ORIAN) system and it was originally designed for the noncontact measurement of rail wear. Since the conception of the ORIAN system, the technology has evolved exponentially and the fulll potential of this innovative rail measurement technology is just beginning to be realized. As this technology further advances it can be adapted to perform even more track structure and geometry measurements. This proposed paper will discuss optical rail profile measurement technology both describing the collection and measurement techniques as well as the type of the data generated.

The dynamic interaction that occurs at the rail/wheel interface of any rail system is significantly influenced by rail and wheel profiles. In an effort to enhance this interaction, railways and transit systems often employ rail grinding as a means to maintain a defined rail profile. The cost to perform this procedure can be very high, sometimes exceeding $DLR25,000 per day for the use of a large grinding machine (with up to 128 grinding motors--each motor being 20 hp or more). Because of this, it is imperative that the work be done efficiently and accurately. In recent years there has been substantial research into the optimization of rail profiles. The National Research Council (NRC) of Canada is one research facility that has generated a unique, precise set of specified profiles for use in heavy-haul railway operations. To implement these profiles in a consistent manner, during rail grinding operations, requires some type of measurement system that provides feedback to the field staff. Up until recently, this has been accomplished with a manual BAR gauge that is fitted with a set of accurate profile templates. The BAR gauge, which initially was fitted with four specified templates, is now equipped with ten such templates. To obtain the full potential of benefits from these profiles requires more precise grinding than that which has been achieved in the past. The other problem with the current manual profile measurement (BAR) method is that it is somewhat slow and cumbersome and the differences between profiles is quite small (i.e. 0.020 inch or less). In order to enhance their rail grinding management support, ARM pursued an automated system that would optically measure rail profiles very fast and accurately from a hy-rail vehicle and compare them with the NRC profiles. Another important feature that was desired in this system was the ability to measure the relative position of one profile with respect to the other (i.e. left versus right rail). Such a system would thus be able to look at both rail profiles in one x-y plane, which is what the manual BAR gauge provides, to produce an electronic simulation of the desired templates oriented with each other in the proper manner, and compares this with the actual profiles. In order to compare actual profiles with the NRC profiles, it is necessary that both rails be looked at simultaneously in one x-y plane. This is mandatory if you want to duplicate the capabilities of the manual BAR gauge. Other parameters such as cant angle, head loss, track gauge, and section rail weight are also calculated at the same time. After evaluating various technologies, ARM selected the Electronic BAR Gauge, manufactured by Range Vision Inc. of Canada. The Electronic BAR Gauge is a second generation piece of equipment that enables you to measure rail profiles and wear within a resolution of 0.001 inch. It is utilized ahead of the grinding program to create a pre-grind survey plan and during grinding operations as a quality control device to verify desired profile installation and to monitor metal removal rates. The Electronic BAR Gauge will help ARM move towards the next generation of rail grinding strategy; namely being able to grind in a true preventive manner, whereby the work is carried out in a predictive manner with just the right amount of metal being removed from the rail in just the right places. This is referred to as the 'magic wear rate'. This paper presents the features of the Electron BAR Gauge, concentrating on how the system has been specifically designed to meet the needs of ARM for their rail grinding applications. Another section describes the accuracy requirements of the system and provides insight on the technology utilized.

A real time system for automated rail inspection and flaw classification at speeds up to 25 mph is described. To maintain a fast testing rate, a distributed multiple processor configuration is used for the high speed portion of the system. A graphics computer provides for real time visualization and playback analysis in a modified B-Scan format. A hierarchical approach is used to distribute the total pattern recognition task into a set of stages in which the recognition results at one stage provide input data of the next stage.

Railroads are a vital transportation link with tracks traversing thousands of miles throughout the United States. When this link fails, the resultant damage costs millions of dollars. Track failure, attributed to moisture trails and erosion voids in the rock ballast and subsoils that support the tracks, slowly deteriorate the rail bed to a critical point in which iron rail shifts occur. All railroad lines experience failures on a regular basis, but the recent flood of 1993, that inundated thousands of square miles of land and hundreds of miles of railroad tracks in the midwestern US, brought a new impetus to quickly locate and repair these hidden subsurface defect areas. This paper illustrates a new technology combination of nondestructive, remote sensing Computer Enhanced Infrared Thermography and Ground Penetrating Radar that was used to detect buried moisture trails and erosion voids of railroad track beds. This technology combination is described in theory and by discussion of a case study based upon a successful project, conducted immediately following the flood, for Burlington Northern Railroad.

High speed tread braking on certain commuter rail cars led to localized shallow tread cracking. Measurement of the temperature gradient into the wheel tread under service conditions was required to confirm the cause and to evaluate potential solutions. This paper describes the tests conducted and the unique instrumentation for measuring the thermal gradient within the wheel tread and is based on a report by Cameron Stuart entitled 'Thermal Measurements of Commuter Rail Wheel Under Revenue Service Conditions'.

Residual stresses in railroad wheels may change from compressive to tensile; this change could lead to wheel failure. The current US regulation calls for the measurement of discoloration indicating heating that may lead to unsafe stress. Quantitative measurement by ultrasonic methods is an attractive alternative, since stress causes small changes in sound velocity. We did an extensive series of measurements on ten cast-steel wheels. Two different ultrasonic instruments gave comparable results. Destructive evaluation of stress in three wheels showed a good correlation with the ultrasonic measurements. This suggests a reliable method and a field-usable instrument for quantitative nondestructive inspection.

A prototype system has been developed for roll-by inspection of cracks in the treads of freight car wheels. The system uses noncontacting electromagnetic-acoustic transducers (EMATs) which generate and receive surface waves propagating along the tread surface. If a defect is present it reflects an echo back to the EMAT. The EMAT itself consists of a coil and permanent magnet which are embedded in a 'rocking shoe'. This device is a piece of impact- absorbing polymeric material having a curvature to match the radius of a 910 mm (36 in) diameter wheel. The rocking shoe is suspended by a spring system in a recess, machined into the outer surface of a rail plug. When the wheel is centered over the shoe, it activates a trigger circuit which energizes the EMAT and causes propagation of the surface wave. The detected echoes are analyzed by a microprocessor which characterizes the wheel as being safe or unsafe. The crack detector system has been subjected to field testing using actual locomotive and rolling stock. It has been able to detect both artificial and real defects at roll-by speeds of 25 km/h (15mph).

The subject of determining the proper profile to use with either the wheel or rail has long been a discussion of controversy. Practices have evolved and become common in monitoring the rail profile and keeping in conformance with research profiles that offer maximum rail life. However, with the wheel, preventative measures to maintain the accepted profile have not been widely adopted. Railroad companies and Loram Maintenance of Way have joined forces to develop an 'automatic wheel inspection system (AWIS). This paper will demonstrate the benefits of monitoring as well as correctively profiling wheels in order to extend their useful life.

A key to gaining an understanding of the bearing failure process and the risk of a catastrophic failure was the measurement of the relative motion between the bearing and the axle under simulated service conditions. The instrumentation and test techniques described here allowed direct measurements of the bearing cone slip during field testing.

To conduct the testing and evaluation of railway and railway vehicles, the Federal Railroad Administration developed a protable system that consists of accelerometers oriented in the vertical and horizontal directions, a Global Positioning System (GPS) receiver, data collection and power systems, and a portable computer. Commercial software was used to collect and display the data, while software, developed by ENSCO, was used to analyze and display results. The GPS provided dynamic location to an accuracy of 30 meters or better, and vehicle speed to within one mile per hour. The system was used in the demonstration tests of several advanced high-speed trains on Amtrak's Northeast Corrider and on other tracks in the US. The portable measurement system proved to be a simple and effective device to characterize the vibration environment of any transportation system. It is ideal for use in the assessment of the safe performance of high-speed trains operating at high cant deficiency. The system has also been used for other field tests, including braking performance and bridge monitoring. This report discusses the portable measurement system, the test applications that the system has been used for, the results of thoses tests, and the potential for improvements.

Burlington Northern Railroad's track geometry measuring car is described along with the techniques and equipment on the car that are used to measure absolute and relative deviations in track geometry. The key parameters being measured are described as well as the methods used to obtain the measurements. The test platform is a passenger coach weighing 110 tons with 3 axle trucks. One of the trucks is instrumented with linear displacement transducers, a tacometer, and laser optics. Track geometry measurements are made at one foot increments along the track and rail profile measurements are at 15 foot increments. Track geometry data is processed in real time at speeds up to 60 mph. Rail profiles can be produced in real time to a limited extent, most of the profile data is post processed. Examples are shown of the real time and post processed track geometry and rail profile reports that are currently produced from meassurement data.

Amtrak's high-speed track geometry measurement car no. 10002 is used routinely on Amtrak's Northeast Corridor (NEC) trackage and on other routes used by Amtrak throughout the country. Data collected by the measurement system is used for many purposes, including: checking compliance with respect to safety standards; maintaining the requirements set forth in the government waiver for 125 MPH operation on the NEC; evaluating the service quality of the track; monitoring the rate of degradation; directing short-term and long-term maintenance programs; evaluating the quality of maintenance work; and serving as inputs in vehicle dynamic modeling. This paper presents brief descriptions of the measurement and data processing capabilities, and examples of applications. Data collected at regular intervals serves as a monitoring tool to measure the quality and the effectiveness of maintenance performed. Data collected at high speed is of particular value in modeling the dynamic performance of high speed passenger trains. Track geometry data processed with the appropriate algorithms can be put into a space curve representation which contains long wavelength information that is critical in higher speed trains. The Amtrak 10002 measures approximately 40,000 miles of track each year. The many applications which use the collected data are a perfect illustration of how modern measurement and data processing technology can be fully integrated into an old industry with established traditional practices.

To improve detection of railroad track defects that cause derailments, the Federal Railroad Administration Office of Research and Development with joint cooperation of the railroad industry developed the Gage Restraint Measurement System (GRMS). This system measures the track's ability to support gage widening forces and marks the locations at risk for derailment. This paper describes the GRMS design, calculated safety indices, and application for use in maintenance planning.

As a direct result of the industry's goal to improve the quality and safety of service to its customers, the Association of American Railroads (AAR) has embarked on a major research project to develop and implement automated inspection methods to effectively measure the available track stength, and to identify and repair the weak spots before further track degradation and increased maintenance are needed. The AAR has designed and constructed a track loading vehicle (TLV) which was used extensively in testing of track lateral restraint. This new vehicle is capable of applying computer controlled loads over a range of track conditions and measure the dynamic response of the track. The TLV is built on the underframe of a diesel-electric locomotive and features a retractable load bogie mounted underneath the center for applying computer controlled loads to the track and measuring the response while stationary or moving. The TLV was successfuly tested over 3,500 miles of revenue track to identify wide gage and weaker tie/fastener conditions. The test results have shown that it is feasible to implement automated inspection methods to effectively measure the available track strength, and to identify and repair the weak spots before further degradation and increased maintenance is needed. Substantial savings could be realized by the industry if positive identification of defective ties can be improved using test devices like the TLV.

During the last decade, research has focused on new and improved track inspection techniques to define the condition of the track structure, and its kwy components. Among the areas of focus for this research has been inspection of the 'strength' or load carrying ability of the track structure. This paper will present the results of a research and development program to implement a track strength analysis and recording (TSAR) system, a hi-rail based system for the measurement of track strength (gage strength under applied load) and track geometry. In this case, a research concept was taken and transformed into a prototype production inspection system which is currently undergoing shakedown and validation and is scheduled to begin production testing June 1, 1995.

Salient Systems, Inc. is developing the technology and the deployment strategy for wayside measurement and reporting of rail longitudinal force due to thermal expansion of CWR. A summary of this work is presented including principles of operation, test sites, and observations. Data are presented showing daily rail stress cycles, trends over weeks and months, and some unique events such as rail movement and winter snows. A perspective is given on the utility of the technology and future plans.

As the condition of our infrastructure continues to deteriorate, and the loads carried by our bridges continue to increase, an ever growing number of railroad and highway bridges require load limits. With safety and transportation costs at both ends of the spectrum. the need for accurate load rating is paramount. This paper describes a method that has been developed for efficient load testing and evaluation of short- and medium-span bridges. Through the use of a specially-designed structural testing system and efficient load test procedures, a typical bridge can be instrumented and tested at 64 points in less than one working day and with minimum impact on rail traffic. Various techniques are available to evaluate structural properties and obtain a realistic model. With field data, a simple finite element model is 'calibrated' and its accuracy is verified. Appropriate design and rating loads are applied to the resulting model and stress predictions are made. This technique has been performed on numerous structures to address specific problems and to provide accurate load ratings. The merits and limitations of this approach are discussed in the context of actual examples of both rail and highway bridges that were tested and evaluated.

This paper describes the organization, procedures, and methodology used by one railroad tank car fleet owner to implement nondestructive testing into the total product cycle for railroad tank cars. The interplay between regulators, design engineering, quality assurance, and field service personnel is discussed as it relates to establishing objectives, responsibilites and mechanisms for the successful implementation of NDT in the life cycle of the tank car nondestructive testing keywords: total product cycle, M-1002.

I am pleased to welcome you to this timely and informative conference organized by The International Society for Optical Engineering (SPIE). As Conference Chair, I am very pleased, but not at all surprised, by your interest and enthusiastic response: Over 300 participants are contributing over 210 technical papers to six topical conferences.

The infrastructure in the United States and the world is aging. There is an increasing awareness o the need to assess the severity of the damage occurring to our infrastructure. Limited resources preclude the replacement of all structures that need repairs or have exceeded their lifetimes. Methods to assess the amount and severity of damage are crucial to implementing a systematic, cost effective approach to repair and/or replace the damaged structures. The challenges of inspecting aging structures without impairing their usefulness rely on a variety of technologies and techniques for nondestructive evaluation. This paper will briefly describe several nondestructive evaluation technologies that re required for inspecting a variety of systems and structures.

the role of the National Laboratory in technology transfer is to help industry implement the latest technology. The National laboratory must have a unique capability that does not compete with tax paying companies. Typically a National Laboratory will demonstrate the benefit of applying NDE to a company's production line. The company then contracts with a vendor to supply a production inspection system based on the laboratory's demonstration. Both the company and the vendor benefit from the participation with the National Laboratory. The company improves the quality of its products and the vendor has a new product to market. The purpose of this paper is twofold: (1) to present a brief overview of NDE capabilities and application activities within the National Laboratory System and (2) to identify NDE point-of- contacts at each laboratory.

This plenary presentation provides a big-picture perspective on the role of NDT/NDE technologies in addressing infrastructure needs, and NDE technology application opportunities in the National Technology Policy context. I will then focus on the Research and Special Program Administration regulatory responsibilities and research coordination activities relevant to the subject of NDE. Finally, on behalf of the Department of Transportation, I will discuss our strategic priorities in R&D and infrastructure renewal. Other DOT participants in this conference--representing the Federal Highway Administration, Federal Aviation Administration, Federal Rail Administration, and our maritime modes--will provide a window on the diverse NDE-related research and technology programs related their missions.