Properties of fouled railroad ballast (phase 1).

Details

• Creators:
  Rahman, A.J. ; Parsons, Robert ; Han, Jie
• Corporate Creators:
  Mid-America Transportation Center
• Corporate Contributors:
  United States. Department of Transportation. Research and Innovative Technology Administration ; United States. Department of Transportation. University Transportation Centers (UTC) Program
• Subject/TRT Terms:
  Ballast (Railroads) Ballast (Railroads)--Deterioration Deterioration Drainage Fouling Permeability Pore Water Pressures Railroad Drainage Resistivity Method
• Publication/ Report Number:
  25-1121-0001-465
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final report.
• Corporate Publisher:
  Mid-America Transportation Center
• Abstract:
  Ballasted tracks are the most common tracks used in the railroad industry and are designed to provide a stable, safe, and efficient rail
  
  foundation. A ballasted track consists of superstructure (ties, fasteners, and rails) and substructure (ballast, sub-ballast, and subgrade
  
  layers). The main functions of ballast are to support the superstructure by distributing the loads from the moving train, and to provide
  
  lateral resistance to tie movement and drainage. However, ballast deterioration and fouling are major issues in the railroad industry, and
  
  can be caused by repeated loadings, which lead to crushing ballast that is in contact with ties. Upward migration of subgrade particles
  
  into the ballast layer can increase fouling in the ballast and decrease drainage through the ballast layer. There is a need for methods to
  
  easily and inexpensively identify areas that have fouled ballast. The objective of this preliminary study was to evaluate the potential for
  
  estimating the level of fouling in a ballast layer by soil resistivity and permeability tests to be followed by a second study. A test box was
  
  designed and fabricated at the lab at the University of Kansas to perform the constant head permeability test and soil resistivity tests.
  
  Constant head tests were conducted to determine the coefficient of permeability of fouled ballast for different fouling percentages. Soil
  
  resistivity tests were also conducted using the Wenner method (4 point method) to determine the resistivity of ballast for different
  
  percentages of fouling. The tests showed a relationship between the percentage of fouling and ballast resistivity. The resistance of the
  
  ballast layer decreased as the percentage of fouling increased due to the presence of water. Fouled material retained water and filled the
  
  voids between the ballast particles, and therefore decreased resistivity in the ballast layer. The permeability (hydraulic conductivity) also
  
  decreased as the percentage of fouling increased due to the presence of fine particles between the ballast particles; therefore,
  
  permeability and resistivity were also correlated
  
  
• Format:
  PDF
• Collection(s):
  University Transportation Centers US Transportation Collection
• Main Document Checksum:
  urn:sha-512:e4491b4d4c6ddf739162be55a0c78c923b2e256bfae3ba843cb68f3237945dd37e2faacda952d6082fe62777988cc63075db7b810b56bd91fa542450e009b2eb
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25427/dot_25427_DS1.pdf
• File Type:
  [PDF - 3.21 MB ]