Beacon Hill tunnel is a public transit tunnel in Seattle, Washington, carrying light rail trains on the 1 Line under Seattle's Beacon Hill between Rainier Valley and SoDo just east of Interstate 5.[1] The Beacon Hill Link Light Rail station is approximately 160 feet (49 m) underground near the midpoint of the tunnel.
 Tunnel's west portal under an elevated portion of Interstate 5 | |
| Overview | |
|---|---|
| Location | Seattle, Washington |
| Coordinates | 47°34′37″N 122°19′12″W / 47.577°N 122.320°W |
| Status | Active |
| Start | SoDo, Seattle, Washington |
| End | Rainier Valley, Seattle, Washington near Mount Baker station |
| Operation | |
| Constructed | 2005–2009 |
| Owner | Sound Transit |
| Traffic | Link light rail (1 Line) |
| Technical | |
| Length | 1 mi (1.6 km) |
| Tunnel clearance | 21 ft (6.4 m)[1] |
| Width | 21 ft (6.4 m)[1] |
Construction
editConstruction of the tunnel began in March 2005 and was completed in July 2009. Obayashi Corporation was the general contractor. The twin running tunnels were excavated with a tunnel boring machine (TBM) built by Mitsubishi, named the "Emerald Mole."[2] The station and crossover tunnels were constructed using the sequential excavation method (SEM), also known as the New Austrian tunnelling method (NATM).[3]
Several workers were injured and one was killed during construction of the tunnel.[4]
The tunnel was completed at a cost of $309 million, versus Obayashi's bid of $280 million.[5]
References
edit
- ^ a b c Beacon Hill Station and Tunnel factsheet (PDF), Sound Transit, 2008[permanent dead link]
- ^ Carl Molesworth (June 5, 2006). "Inside the Emerald Mole". Pacific Builder and Engineer. Archived from the original on 2008-02-14.
- ^ "Sound Transit digs a cutting-edge tunnel". DJC. Retrieved 2009-09-17.
- ^ Levi Pulkkinen; Larry Lange (February 7, 2007), "Worker killed in Sound Transit tunnel: Second accident in three months at light rail site", Seattle Post-Intelligencer
- ^ Eric de Place (October 2009), Sightline Report: Cost Overruns For Seattle-Area Tunnel Projects (PDF), Sightline Institute, retrieved 2013-04-04[permanent dead link]