Under present AAR rules governing removal of flat wheels, flat spots are limited to 2-1/2 in. length for one slid flat and 2 in. each for adjoining spots on freight car wheels and 1 in. on passenger car wheels. These limitations have been established from the experience and judgment of those concerned with the operation and maintenance of equipment and track. To date mathematical solutions to evaluate the impact effects from flat spots have not been adequate. Until recent years, instruments of sufficiently high frequency response to accurately measure the rapid stress changes have not been available. Tests made on the New York, New Haven, and Hartford RR. in 1942 established the characteristics required for reliable instrumentation. Suitable stress measuring instruments were obtained and a comprehensive test program to determine the effects of flat spots on both the track and equipment was conducted on the Chicago & North Western Railway during the summer of 1947. A special test train was used consisting of a locomotive, a passenger car carrying the measuring and recording instruments for the measurements on the test car, and a flat test car having a flat wheel and loaded with rails.

  • Supplemental Notes:
    • This report was prepared by the Joint Committee on Relation Between Track and Equipment.
  • Corporate Authors:

    Association of American Railroads Research Center

    3140 South Federal Street
    Chicago, IL  United States  60616
  • Publication Date: 1951-5

Subject/Index Terms

Filing Info

  • Accession Number: 00044524
  • Record Type: Publication
  • Source Agency: Association of American Railroads
  • Report/Paper Numbers: MR-113
  • Files: TRIS
  • Created Date: Jun 15 1976 12:00AM