Performance of No. 20 Frogs of Various Designs in Revenue Service

Transportation Technology Center, Inc. (TTCI) tested and evaluated the performance of four No. 20 fixed-point frogs on the Norfolk Southern Railway (NS) track as part of the jointly funded Association of American Railroads (AAR) and Federal Railroad Administration (FRA) Heavy Axle Load (HAL) Revenue Service Test Program (Jimenez, Davis, Shu, & Aragona, 2016). Two standard frog systems used by the host railroad and two premium frog systems were installed specifically for this test within a 54-mile section of track south of Lexington, Kentucky, between March and August, 2013. Each frog is defined as a system due to several noteworthy differences (e.g., point thickness, under-plate pads) among them. As of April 1, 2016, the frogs have accumulated between 226 and 234 million gross tons (MGT) of traffic. Performance of the four frog systems was evaluated based on the following criteria: periodic visual inspections, wear/deformation of the running surfaces over time/tonnage, and reporting of any required maintenance over the course of the test. In addition, the dynamic service environment was characterized by way of dynamic response measurements under train traffic. The wider heavy points of the premium frogs had approximately 50 percent less deformation than the points of the standard frogs under the same traffic as of September 2015. The mainline route wings of the premium frogs had approximately 33 percent less deformation than the mainline route wings of the standard frogs. The design of the frog heel/frog heel-rail interface on the premium frogs reduced running surface deformation by approximately 50 percent as compared to the standard frog heel designs. The dynamic service environment measurements indicated a generally less severe condition over the premium frogs. Results from this test suggested that safety will be improved through lower wear and fatigue rates with improved performance frogs. The decreased dynamic loads should also contribute to fewer vehicle component failures. The four frogs, located in turnouts that control passing sidings in a single-track railroad, remained in service for continued performance monitoring.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References; Tables;
  • Pagination: 4p
  • Serial:
    • Research Results
    • Issue Number: RR 18-04
    • Publisher: Federal Railroad Administration
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 01666134
  • Record Type: Publication
  • Created Date: Apr 16 2018 8:46PM