The aerodynamic forces on trailers and containers on flatcars have been measured in wind tunnel tests. The forces were measured on the central car of a five-car train consisting of a locomotive, three flatcars with various loadings and a boxcar. Tests were made over a range of yaw angles and with different loadings. Standard trailers, containers and flatcars were tested as well as a variety of modifications designed to improve the aerodynamic performance. In addition to the railroad-car tests, a series of blocks simulating containers and trailer bodies were tested to determine the effect of gap spacing, corner radius, and surface roughness. The flatcars loaded with containers were found to have about forty percent less drag than when loaded with trailers. Various modifications that reduced the frontal area of the trailers or filled in the empty space between the trailer body and the car were all found to be effective in reducing the drag. Gap spacing size had little effect until it became of the order of the body width, and then the drag increased with increased spacing. Side and lift forces are chiefly caused by yaw angle and side area. The forces act near the centroid of the side area, but when the gap spacing becomes large they move farther forward. The research reported is intended to increase the knowledge base in understanding the aerodynamic drag component of trail resistance.

  • Record URL:
  • Supplemental Notes:
    • Research was sponsored by the FRA, Office of Research and Development, under contract to the Transportation Systems Center, Cambridge, Massachusetts.
  • Corporate Authors:

    Hammitt (Andrew G) Associates

    30813 Marne Drive
    Rancho Palos Verdes, CA  United States  90274
  • Authors:
    • Hammitt, A G
  • Publication Date: 1976-12

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 150 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00147713
  • Record Type: Publication
  • Source Agency: Federal Railroad Administration
  • Report/Paper Numbers: FRA/OR&D-76-295.1 Final Rpt.
  • Contract Numbers: DOT-TSC-1002-1
  • Files: NTL, TRIS, USDOT
  • Created Date: Feb 16 1977 12:00AM