Technical Reports

Study of Bridge Approach and Track Transition Degradation: Factors and Mitigation

  • 01
  • Oct
  • 2003
AUTHOR: Lamont Smith, Brian Doe, Dingqing Li, Duane Otter, Shakoor Uppal
SUBJECT: Bridge and Structures Safety
KEYWORDS: Track Transition, Geometry Degradation, Factors and Causes
ABSTRACT: Efforts have been made to reduce or eliminate track geometry degradation at bridge approaches and special trackwork zones for more than a century. This is a common problem that has been reported by railroads in North America, Europe, Asia, South America, and Australia. The objective of this report is to determine the entire range of variables that can contribute to these degradation problems and to examine the effectiveness of the many types of mitigation methods. This report summarizes the study of actors and mitigation methods as related to bridge approach and track transition degradation. The study was conducted based on a literature review, interviews with field personnel, and field investigations and tests.The studies performed resulted in a vast array of characteristics to consider when analyzing the reasons for track degradation at these locations. The array of potential remediation methods is nearly as broad and diverse.The findings show that the geotechnical aspects of the track geometry degradation problem are every bit as important as the consideration of the vertical stiffness transition between the approach and bridge span. By taking into consideration the importance of geotechnical characteristics, such as consolidation factors, compaction, moisture content control, erosion, vegetation control, ballast quality, and quality of backfill material and construction the railroad industry should be able to gain better control of this problem. This would result in monetary savings in track repair labor and speed or other operating restrictions.