Technology Digests / Rail Temperature Monitoring at FAST®

TD25-029

February 10, 2026
Authors
  • Stephen Wilk
  • Kenny Morrison
  • Christopher Johnson
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Key Findings

  • During summer months, FAST experiences rail temperatures up to 142°F with no train influence.
  • Rail temperature increases due to solar radiation generally ranged from 25 to 35 degrees (°F) but reached a 41-degree increase during specific weather conditions.
  • A single pass from the FAST train (i.e., typical loaded bulk commodity unit train) increased rail temperatures by 1 degree in tangent track, 3 degrees in a lubricated six-degree curve, and 5 degrees in an unlubricated six-degree curve. These rail temperature increases are attributed to frictional contact. Quantity of wheelsets, axle load, track degree of curvature, and lubrication are all anticipated to affect these rail temperature increases.

Rail Temperature Monitoring at FAST®

MxV Rail has been monitoring rail temperatures at the Facility for Accelerated Service Testing (FAST®) since January 2024.1 The measurements are taken primarily to monitor rail temperatures during FAST operations but also to provide a comprehensive dataset from Pueblo, CO, that can be used to quantify rail temperatures from both solar radiation and train operations. Rail temperatures are difficult to measure without wayside equipment, and the historical rule-of-thumb supposes that daytime solar radiation increases rail temperatures above ambient by 30°F.2 In addition, there is little information on train-induced rail temperatures apart from unique situations, such as sustained air braking down long steep grades.3 The primary purpose of this Technology Digest is to provide summary documentation for the measured FAST rail temperatures from January 2024 to August 2025. While the specific rail temperatures are unique to Pueblo, CO, and the FAST operating environment, aspects relevant to a more diverse geographic area…