Experience in standardization and soft-ground tunneling for the underground railways of London are reviewed, and metric conversion in the construction industry and in the tunneling industry are discussed. Standardization of expertise is illustrated by the existence in Britain of contractors specializing in underground construction and those specializing in tunneling. A measure of standardization of running tunnel diameter was instituted in 1924. The shape of the load gauge and its limited dimensions, the absolute minimum clearance that must be assured around the outside of the vehicle to determine the structure gauge are important basics in standardizing the cross-sectional area of a railway tunnel. Walking space requirements are also incorporated. Different requirements in different cities determine the shape of the vehicle. The standard tunnel diameter dating back to 1900 is 11 ft. 8 1/4 inch and the standard station tunnel diameter (internal) is 21 ft. 2 1/2 inch. Departure from the standards (in 1907) and the reasons for it are set forth. Comments are made on the variations of conditions from city to city and the impracticability of applying the same standards in all cities. The standardization of machinery and equipment for tunneling, underground construction and mining are also discussed. Metric conversion has occured in the tunneling industry because the construction industry has gone metric. The conversion has been monetarily costly. However, a peculiar situation exists: the engineers have metricated while users of the infrastructure, the operating personnel and others have not.

  • Supplemental Notes:
    • Report of a symposium conducted by Standing Subcommittee No. 5, International Activities of the U.S. National Committee on Tunneling Technology, held on May 21-22, 1974 in Washington, D.C.
  • Corporate Authors:

    National Research Council

    National Committee on Tunneling Technology
    Washington, DC  United States  20418
  • Authors:
    • Follenfant, H G
  • Publication Date: 1975

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Filing Info

  • Accession Number: 00127932
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 21 1981 12:00AM