Technical Reports

FAST/HAL Tie and Fastener Experiments

  • 01
  • Dec
  • 1991
AUTHOR: Dave Read
SUBJECT: Facilities & Test Equipment
KEYWORDS: Facility for Accelerated Service Testing, Heavy Axle Load, Wood Ties, Concrete Ties, Fastener Systems
ABSTRACT: The objective of the Fast Accelerated Service Testing Heavy Axle Load Tie and Fastener Experiments was to quantify the performance of wood and concrete ties and associated fastening systems under the FAST Heavy Axle Load (HAL) train. The experiment was conducted on the 5- and 6-degree curves of the High Tonnage Loop (HTL), with total tonnage accumulation of 160 million gross tons (MGT). Fastener stiffness measurements performed on wood ties indicated the cut spike system allowed at least twice the lateral rail head displacement of any elastic fastener at a L/V ratio of 0.5. The cut spikes also showed as much as five times the rate of lateral restraint degradation as the elastic fasteners over the 160 MGT period at the 0.5 L/V ratio. However, at L/V ratios of 0.25 or less, the lateral displacement allowed by the cut spikes were nearly identical to the elastic fasteners. Comparison of static rail rotation data taken during the 33-ton axle load phase of testing at FAST indicates 70-100 percent higher values are being recorded under the 39-ton axle load consist. Flexural cracks were observed during the initial 90 MGT on 3 percent of the concrete ties in test. The cracks all occurred on the low rail side of the tie between the rail seat and the tie center and were caused by negative bending of the tie. Similar cracks were also observed on one of the concrete ties designed for tangent track. There were no new cracks noted after 90 MGT. None of the cracked ties were removed from track; some remained in service for 140 MGT after crack initiation. Similar cracking was not noted during the 33-ton axle load phase.