Taller Tunnels

by Gerry Millar, Vice Pres.; Shannon and Wilson, Inc., Seattle, WA,
Harvey W. Parker, Sr. Vice Pres.; Shannon and Wilson, Inc., Seattle, WA,
Paul M. Godlewski, Assoc.; Shannon and Wilson, Inc., Seattle, WA,

Serial Information: Civil Engineering—ASCE, 1991, Vol. 61, Issue 9, Pg. 50-53

Document Type: Feature article


Between 1984 and 1991, Shannon & Wilson, Inc., Seattle, designed renovation programs for more than 25 mi of tunnels for four western railroads. We performed all of this work under live-track conditions, during periods of high traffic volume, in single-track tunnels. We had to complete each construction operation in a work window lasting 1-6 hours. We generally did not know the timing and length of a window until 30 min prior to its beginning and end. This required materials and methods that could be implemented safely and efficiently in short work periods. As many as 20 individual tunnels were included in a contract package and handled by one work-train setup. This meant that the equipment would have to be moved as far as 10 mi from its mobilization siding to work areas that often were inaccessible by road. Scheduling often required work in more than one tunnel at a time. With this situation, the equipment setup had to be very flexible, and the crews had to have a degree of mobility and organization rarely required in underground work. We studied track undercutting, open cuts and crown mining as rehabilitation methods, using the latter for almost all work. For most linings, we achieved the required clearance by cutting a pair of notches running the length of the tunnel crown.

Subject Headings: Tunnels

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