Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The latest general information on the Coronavirus Disease 2019 (COVID-19) is available on the CDC website.

United States Department of Transportation United States Department of Transportation

Heat-Assisted Tunnel Boring Machines

Document Series
Technical Reports
J. P. Carstens, W. R. Davison, C. A. Brown, A. R. Smith, F. J. McGarry
Report Number
Subject Facilities & Test Equipment, Tracks & Structures
Tunneling Machine Performance, Laser Technology, Excavation

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact
Last updated: Tuesday, September 1, 1970