A Frog Design Primer and Research Roadmap

The frog is a component of special trackwork where one rail crosses another. Openings called flangeways are provided in standard frogs so that the flanges on the vehicle wheels can pass through. When the wheel passes through the open flangeway at the point of the frog, the wheel tread and frog wing rail surface locations produce high impact forces, noise, and vibration. When frogs must be located near noise- and vibration-sensitive land uses, they are often identified as having impacts during the environmental review process and require mitigation. Flange bearing frogs are typically used in standard light rail track on streets.  Low-impact frog designs can reduce noise and vibration levels. However, there is almost no publicly available data on how effectively low-impact frog designs reduce noise and vibration levels, their longevity, and their maintainability. As a result, many agencies are hesitant to adopt new frog designs. The objectives of this project are to develop (1) a frog design primer and (2) a research roadmap. The primer is to provide guidance to transit agencies on how to select appropriate frog designs for noise and vibration mitigation and how to maintain good noise and vibration performance through effective maintenance practices. The research roadmap should be built on analyses of frog systems, informed by current practices and a literature review focused on the reduction in noise and vibration provided by alternative low-impact frog designs. The research roadmap is intended to be used by the rail transit community to focus its efforts to foster, support, monitor, disseminate, and implement research on frog system design. The roadmap will build upon existing research and will be informed by outreach to the active rail design, procurement, operations, and maintenance practitioner community. In addition to identifying research gaps and prioritizing research needs, the roadmap should foster collaboration with standards development organizations such as the American Public Transportation Association (APTA) and AREMA.


  • English


  • Status: Active
  • Funding: $300000
  • Contract Numbers:

    Project D-22

  • Sponsor Organizations:

    Transit Cooperative Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    Federal Transit Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Garcia-Colberg, Mariela

  • Performing Organizations:

    Cross-Spectrum Acoustics

    East Longmeadow, MA  United States 
  • Principal Investigators:

    McKenna, Shannon

  • Start Date: 20240528
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01789438
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project D-22
  • Files: TRB, RIP
  • Created Date: Nov 23 2021 6:56PM