This study was carried out for the Transportation Systems Center of the U.S. Department of Transportation on behalf of the Urban Mass Transportation Administration in order to determine to what degree it is possible to attenuate the effects of pressure pulses on the passengers in trains entering tunnels. The emphasis of this study is on the approach of modifying the normal, abrupt entry portal of the constant diameter single-track tunnel. In order to understand this approach, which requires the tailoring of a tunnel portal, it was first necessary to have an analytical model in which confidence exists in its capability to predict realistic pressure pulse histories of trains entering tunnels having porous and/or flared entry portals. To accomplish this, the best available theoretical information along with small-scale laboratory experiments were used to update an existing computer program. Then, this program was used to demonstrate effective portal configurations. Although reasonable modifications to the tunnel entrance portal may not decrease the magnitude of the pressure rise, they are very effective in reducing the discomfort to the human ear by decreasing the rate of pressure rise to what the normal ear can accomodate. A brief qualitative comparison was made of this portal modification approach with other approaches: decreasing the train speed during the tunnel entry and sealing the cars. The optimum approach, which is dependent upon the conditions and requirements of each particular rail system, is likely to be the portal modification one for the subway transit system.

  • Corporate Authors:

    Jet Propulsion Laboratory

    California Institute of Technology, 4800 Oak Grove Drive
    Pasadena, CA  United States  91103

    Transportation Systems Center

    55 Broadway, Kendall Square
    Cambridge, MA  United States  02142

    Urban Mass Transportation Administration

    Office of Tech Development & Deployment, 400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Dayman, B J
    • Holway, H P
    • Hammitt, A G
    • Tucker Jr, C E
    • VARDY, A E
  • Publication Date: 1979-6

Media Info

  • Pagination: 235 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00199098
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: DOT/TSC/UMTA-79/28 Final Rpt., UMTA-MA-06-0100-7910
  • Contract Numbers: DOT-RA-N-02-612-0397
  • Files: NTIS, TRIS, USDOT
  • Created Date: Dec 19 1981 12:00AM