Technical Reports

High-Speed Rail Turnout Literature Review

  • 10
  • Aug
  • 2016
AUTHOR: Federal Railroad Administration
KEYWORDS: Turnout geometry and design criteria, switch rail optimization, track stiffness, components
ABSTRACT: High-speed rail (HSR) turnout design criteria generally address unbalanced lateral acceleration or cant deficiency (CD), cant deficiency change rate (CDCR), and entry and exit jerk. Various countries have adopted different design values for their HSR systems based on their unique experiences and operating conditions. The design criteria (e.g., one for unbalanced lateral accelerations and jerk) have a direct influence on passenger ride comfort, but cannot be used as performance indices because they only account for kinematic responses, not dynamic responses. In North America, vehicle and turnout dynamic performances must comply with ride comfort and safety standards, such as FRA Track Safety Standards, Part 213. In a worldwide market, vehicle and track performance will most likely comply with ISO 2631. Switch rail optimization methodologies, such as Kinematic Gage Optimization and rail reprofiling, have demonstrated their effectiveness in reducing wheel force, rail force and rail wear through improved axle steering capability. The presteer switch was originally designed for North American low-speed turnouts, and its performance on HSR should be examined. Track stiffness uniformity along a turnout is critical for HSR operation. Proper track transition and optimal track stiffness can reduce wheel and rail impact forces while improving ride quality.