Project Description

In the early 1990s, LACHEL & Associates (LFA) performed an initial inspection and preliminary feasibility study of the UPRR Stampede Tunnel in Washington State.

The Stampede Tunnel was originally constructed to transverse the Stampede Pass of the Cascades for the Northern Pacific railroad. The original tunnel was completed in 1888 and replaced seven miles of switchbacks by bypassing the steepest sections of the pass. The tunnel has a total length of 9,832 feet with an excavated height of 22 feet and a width of 16 feet. The original tunnel was primarily unlined but shortly after construction, limited sections of the tunnel were retrofitted with concrete and brick linings to support areas of marginal rock.

Scope of Services

At the time of the inspection the railroad line had been abandoned for a number of years. The tunnel approaches were obstructed and a fire had destroyed the timber snow sheds at the portals and damaged some of the tunnel lining. LACHEL & Associates briefly inspected both of the portals as well as the accessible interior portions of the tunnel. LFA, as a subconsultant to HDR Engineering, documented the existing tunnel conditions and provided initial recommendations for tunnel rehabilitation.

Ultimately, the Stampede Tunnel was rehabilitated and reopened for rail traffic in 1996.

Client

HDR Engineering, Inc.
Union Pacific Railroad