FAST/HAL Ballast and Subgrade Experiments

The ballast and subgrade experiments were conducted during the first 160 million gross tons (MGT) of Heavy Axle Load (HAL) traffic to determine if the increase in axle load, 33-ton to 39-ton, generated a measurable difference in the performance of the four selected ballasts and the typical subgrade found at the Facility for Accelerated Service Testing (FAST), Transportation Test Center, Pueblo, Colorado. Dolomite, limestone, granite, and traprock were tested to determine their capability of supporting traffic in a 39-ton axle load traffic environment. Track geometry retention and ballast degradation were monitored during the test. All four ballasts were able to withstand the HAL environment, but the dolomite and limestone required an out-of-face surfacing before the end of the first phase of the HAL program. The Subgrade Experiment was conducted to determine if an increase in axle load produces a significant increase in subgrade stresses. Data from the test reflected the increase in axle load at the ballast/subgrade interface. The increase varied with the track support condition.

  • Record URL:
  • Corporate Authors:

    Association of American Railroads

    Transportation Test Center, P.O. Box 11130
    Pueblo, CO  United States  81001

    Association of American Railroads Technical Center

    3140 South Federal Street
    Chicago, IL  United States  60616

    Federal Railroad Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Trevizo, M Carmen
  • Publication Date: 1991-8


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 128p

Subject/Index Terms

Filing Info

  • Accession Number: 01666432
  • Record Type: Publication
  • Report/Paper Numbers: FRA/ORD-91/10, R-788
  • Contract Numbers: DTFR53-82-C-00282
  • Files: TRIS, ATRI, USDOT
  • Created Date: Mar 12 2018 2:09PM