Technical Reports

FAST Heavy Axle Load Ballast Test Results

  • 01
  • Dec
  • 1997
AUTHOR: M. Carmen Trevizo
SUBJECT: Facilities & Test Equipment
KEYWORDS: Facility for Accelerated Service Testing, TTC, Ballast Materials, Ballast Performance
ABSTRACT: A ballast experiment was performed at the Federal Railroad Administration’s Transportation Technology Center, Facility for Accelerated Service Testing (FAST), Pueblo, Colorado, as part of the original series of tests designed to determine track performance under 39-ton axle loads. Four ballast materials — granite, traprock, limestone and dolomite — were installed in the High Tonnage Loop (HTL) in 1988. Even though a direct comparison between 33- and 39-ton axle load traffic cannot be made due to differences in ballast types and accumulated tonnage, it appears that degradation of the material in test is more dependent on accumulated tonnage than on increased axle load. The granite and traprock ballast maintained adequate geometry throughout the 750 MGT duration of the test, while the dolomite required an out-of-face surfacing after the first 40 MGT and again after the first 260 MGT, after which it was removed from track. The limestone required surfacing after the first 70 MGT of traffic. The primary objective of the experiment was to quantify ballast performance based on measurements of track geometry, ballast density, track settlement, and ballast particle degradation. A secondary objective was to quantify the amount of fine material in the ballast generated by track maintenance.