Technology Digests / Friction Modifier Interaction with Rolling Contact Fatigue at FAST®

TD26-009

Date Posted: May 28, 2026
Authors
  • Ulrich Spangenberg
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Key Findings

  • Rolling contact fatigue (RCF) deterioration occurred at and near the friction modifier applicator bars of FAST at a fixed wavelength that corresponded to a 38-inch wheel revolution of FAST gondolas.
  • Analysis suggests that the RCF initiated first and was later exacerbated by the friction modifier product.
  • Grinding to the south of the applicator bars appeared to be beneficial, suggesting that grinding could be an effective treatment of similar RCF deterioration near friction modifier applicators.
  • Due to the relative proximity of TOR-FM applicators at FAST, fine-tuning of the TOR-FM output rates may also reduce interaction between the TOR-FM product and RCF.

Friction Modifier Interaction with Rolling Contact Fatigue at FAST®

MxV Rail studied the rail deterioration observed near the top-of-rail (TOR) friction modifier (FM) applicator bars on track at the Facility for Accelerated Service Testing (FAST®). The study, part of the Association of American Railroads (AAR) Strategic Research Initiative (SRI) program, was conducted to determine the root cause and contributing factors in order to avoid similar deterioration in future. INTRODUCTION FAST employs gage face lubricant and TOR-FM to reduce wheel flange wear, rail gage face wear, and curving forces. The gage face lubricant is applied before the start of the northernmost 6-degree curve, whether traveling clockwise or counterclockwise (see Figure 1). FAST operates as a closed loop, thus the TOR-FM applicator spacing is 2.8-miles, which is different to the typical 6- to 8-mile spacing used in revenue service. TOR-FM applicators were originally co-located with the gage face lubricators at either end of Section 5. One TOR-FM applicator was removed, and…