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  • Schlake et al. 09-2863 1

    Automated Inspection of Railcar Underbody Structural Components Using Machine Vision Technology

    09-2863

    Bryan W. Schlake – Corresponding Author Graduate Research Assistant

    University of Illinois at Urbana-Champaign Railroad Engineering Program

    B-118 Newmark Civil Engineering Lab 205 N. Mathews Ave., Urbana, IL, USA 61801 Phone: (217) 244-6063 Fax: (217) 333-1924

    Email: schlake@illinois.edu

    J. Riley Edwards Lecturer

    University of Illinois at Urbana-Champaign Railroad Engineering Program

    1201 Newmark Civil Engineering Lab 205 N. Mathews Ave., Urbana, IL, USA 61801 Phone: (217) 244-7417 Fax: (217) 333-1924

    Email: jedward2@illinois.edu

    John M. Hart Senior Research Engineer

    University of Illinois at Urbana-Champaign Coordinated Science Laboratory

    Computer Vision and Robotics Laboratory 3021 Beckman Institute for Advanced Science and Technology

    405 N. Mathews Ave., Urbana, IL, USA 61801 Phone: (217) 244-4174 Fax: (217) 244-8371

    Email: jmh@vision.ai.uiuc.edu

    Christopher P.L. Barkan Associate Professor

    University of Illinois at Urbana-Champaign Director - Railroad Engineering Program

    Department of Civil and Environmental Engineering 1203 Newmark Civil Engineering Laboratory

    205 N. Matthews Ave., Urbana, IL, USA 61801 Phone: (217) 244-6338 Fax: (217) 333-1924

    Email: cbarkan@illinois.edu

  • Schlake et al. 09-2863 2

    Sinisa Todorovic Postdoctoral Associate

    University of Illinois at Urbana-Champaign Computer Vision and Robotics Laboratory

    Beckman Institute for Advanced Science and Technology 405 N. Mathews Ave., Urbana, IL, USA 61801 Phone: (217) 244-4174 Fax: (217) 244-8371

    Email: sintod@vision.ai.uiuc.edu

    Narendra Ahuja Professor

    University of Illinois at Urbana-Champaign Department of Electrical and Computer Engineering

    Computer Vision and Robotics Laboratory 2041 Beckman Institute for Advanced Science and Technology

    405 N. Mathews Ave., Urbana, IL, USA 61801 Phone: (217) 333-1837 Fax: (217) 244-8371

    Email: n-ahuja@illinois.edu

    Word Count: 250 (Abstract) + 4,784 (Text) + 7 Figures = 6,784 Words

    Submitted November 15, 2008

  • Schlake et al. 09-2863 3

    ABSTRACT Monitoring the structural health of railcars is important to ensure safe and efficient railroad operation. The structural integrity of freight cars depends on the health of certain structural components within their underframes. These components serve two principal functions: supporting the car body and lading and transmitting longitudinal buff and draft forces. Although railcars are engineered to withstand large static, dynamic and cyclical loads, they can still develop a variety of structural defects. As a result, Federal Railroad Administration (FRA) regulations and individual railroad mechanical department practices require periodic inspection of railcars to detect mechanical and structural damage or defects. These inspections are primarily a manual process that relies on the acuity, knowledge and endurance of qualified inspection personnel. Enhancements to the process are possible through machine vision technology, which uses computer algorithms to process digital image data of railcar underframes into diagnostic information.

    This paper describes research investigating the feasibility of an automated inspection system capable of detecting structural defects in freight car underframes and presents an inspection approach using machine vision techniques including multi-scale image segmentation. A preliminary image acquisition system has been developed, field trials conducted and algorithms developed that can analyze the images and identify certain underframe components, assessing aspects of their condition. The development of this technology, in conjunction with additional preventive maintenance systems, has the potential to provide more objective information on railcar structural condition, improved utilization of railcar inspection and repair resources, increased train and employee safety, and improvements to overall railroad network efficiency.

  • Schlake et al. 09-2863 4

    INTRODUCTION In the United States, railcars undergo regular mechanical inspections as required by Federal Railroad Administration (FRA) regulations and as dictated by railroad mechanical department practices. These mechanical inspections address numerous components on the railcar including several underbody components that are critically important to the structural integrity of the railcar. The primary structural component, the center sill, runs longitudinally along the center of the car, forming the backbone of the underframe and transmitting buff and draft forces through the car (1). In addition to the center sill, several other structural components are critical to load transfer, including the sidesills, body bolsters, and crossbearers. The sidesills are longitudinal members similar to the center sill, running along the entire length of the car on either side. Body bolsters are transverse members near each end of the car that transfer the car’s load from the car body to the trucks. Crossbearers are transverse members that connect the sidesills to the center sill and help distribute the load between the longitudinal members of the car. These components work together as a system to help maintain the camber and structural integrity of the car. Mechanical Regulations and Inspection Procedures FRA Mechanical Regulations require the inspection of center sills for breaks, cracks, and buckling, and the inspection of sidesills, crossbearers, and body bolsters for breaks, as well as other selected inspection items (2). Over 1.6 million freight cars are in service throughout North America. Each time one of these cars departs a yard, terminal, or industrial facility it is required under Federal Railroad Administration (FRA) regulations to be inspected by either a qualified mechanical inspector, referred to as a carman, or a train crew member for possible defects that would adversely affect the safe operation of the train. The current railcar inspection process is tedious, labor intensive, and in general lacks the level of objectivity that may be achievable through the use of new technology. In order to effectively detect structural defects, car inspectors would need to walk around the entire car and crawl underneath with a flashlight to view each structural component. Due to time constraints associated with typical pre-departure mechanical inspections, cars are only inspected with this level of scrutiny in car repair shops before undergoing major repairs. In addition to the inherent safety concerns and efficiency challenges of manual inspections, records of these inspections are generally not retained unless a billable repair is required, making it difficult to track the health of a car over time or to perform a trend analysis. As a result, the maintenance of railcar structural components is almost entirely reactive rather than predictive, making repairs and maintenance less efficient. To address these concerns, a number of automated systems have been developed to inspect various railcar components through the use of cameras, sensors, and other non-destructive inspection methods. These technologies have the potential to improve inspection efficiency and reduce the time that car inspectors are exposed to the hazards of the rail yard environment. Technology Driven Train Inspection (TDTI) The Association of American Railroads (AAR) along with the Transportation Technology Center, Inc. (TTCI) has initiated a program intended to provide safer, more

  • Schlake et al. 09-2863 5

    efficient, and traceable means of rolling stock inspection (3). The object of the Technology Driven Train Inspection (TDTI) program is to identify, develop, and apply new technologies to enhance the efficiency and effectiveness of the railcar inspection, maintenance, and repair process. Examples of these new technologies include the automated inspection of railcar trucks, safety appliances and passenger car undercarriages (4, 5, 6). The ultimate objective of TDTI is to implement a network of automatic wayside inspection systems capable of inspecting and monitoring the North American freight car fleet in order to maintain compliance with FRA regulations and railroad- specific maintenance and operational standards. In order for this automated inspection initiative to improve safety and enhance the efficiency of current railcar mechanical inspections, the final wayside inspection systems must be holistic in scope. As a result, TDTI has initiated the development of separate automated inspection technologies that will address each aspect of the federally-mandated freight car inspection. Automated Inspection of Structural Components (AISC) One aspect of the TDTI initiative is the development of the system known as Automated Inspection of Structural Components (AISC), which is currently underway at the University of Illinois at Urbana-Champaign (UIUC). AISC focuses on developing technology to aid in the inspection of freight car underbodies for defective structural components through the use of machine vision. A machine vision system acquires data using digital cameras, organizes and analyzes the images using computer algorithms, and outputs useful information, such as the type and location of defects, to the appropriate repair personnel. The machine vision algorithms use visual cues to locate areas of inte

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