Technology Digests / Effects of Superelevation and Train Speed on Rail Performance

TD22-029

October 1, 2022
Authors
  • Chris Pinney
  • Ananyo Banerjee
  • Anish Poudel
  • Ryan Alishio
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Key Findings

  • The 6.2-degree test curve operated at 1 inch SE deficiency (1.5-inch SE) performed better than the 6.2-degree test curve operated at 1 inch SE excess (3.5-inch SE) with regard to RCD accumulation as evaluated using EMFI rail scans, PT rail surface condition assessments, and depth-of-cut rail grinding results.
  • EMFI test results showed the 3.5-inch SE curve having statistically greater RCD severity on the low and high rails compared to the 1.5-inch SE curve.
  • Visual inspection using PT methods suggests RCD for the 3.5-inch SE curve is slightly more severe on high rails and moderately more severe on low rails compared to 1.5-inch SE test curve.
  • Grinding analysis indicates more severe RCD on the test curve with 3.5 inches of SE, notably severe spall and head checking on the low rail and light head checking on the high rail.
  • Simulations indicated a lower wear index for the the low rail of the 1.5-inch SE curve. However, there was no statistical wear difference between the curves through 146 MGT.

Effects of Superelevation and Train Speed on Rail Performance

MxV Rail (formerly TTCI) conducted research on two 6.2-degree test curves to understand the effects of superelevation (SE) and speed on rail performance. The SE was the primary test variable between the curves. Based on the median operating speed recorded at the test site (~24 mph), balance SE for the 6.2-degree test curves was 2.5 inches. For the test, one curve was designed with 1 inch of SE deficiency at ~1.5 inches, while the other curve was designed with 1 inch of SE excess at ~3.5 inches. The objective of this research was to quantify the effects of elevation deficiency or elevation excess on rail performance when operating trains in revenue service.1,2 Test results evaluated rail wear and rolling contact damage (RCD) as performance criteria between test curves for both high and low rails. The testing methods used MiniProf rail profile measurement equipment to evaluate rail wear. RCD was evaluated…