SEATTLE — One of the biggest construction projects in the Pacific Northwest in recent years is actually a demolition job — the removal of a two-mile double-decker elevated highway slicing between downtown and the Elliott Bay waterfront.
And slicing under that highway structure is one of the region’s most important rail lines.
BNSF Railway’s main line runs north from King Street Station into a double-tracked one-mile-long tunnel beneath downtown Seattle, emerging along the waterfront near Pike Place Market. The line runs north to Everett, Wash., then north to Vancouver, British Columbia, or east to Stevens Pass and across the northern tier of states via the Great Northern’s route.
The downtown segment is used by freight trains, Amtrak Cascades service, Amtrak’s Empire Builder, and Sound Transit’s Sounder commuter trains. The tunnel was opened in 1904 to reduce the tangle of rail lines snarling traffic in the city.
The Alaskan Way Viaduct, built in the 1950s, was also an effort to unsnarl traffic. While bemoaned for its appearance and noise, and for serving as a barrier between the city’s center and the waterfront, it proved to be a critical corridor for traffic, handling more than 100,000 cars a day.
But damage from a previous earthquake and concerns about its stability should the Big One strike led to a proposal for, and then construction of, a highway tunnel under the city to replace the viaduct.
With the tunnel now open, work has begun on dismantling the viaduct, a tricky endeavor because of how much has been built and how close buildings, utility lines, roads, and other infrastructure items are to the highway.
The railroad was there first, and its overlap with the viaduct is short compared to buildings built within five feet of the viaduct, but it’s one more object to work around without disrupting or damaging it.
Details of how that will be accomplished are still being worked out.
“The Washington State Department of Transportation, Kiewit Infrastructure West and BNSF are coordinating all demolition efforts and there is a specific demolition plan in place for viaduct demolition that takes place over the BNSF tracks,” wrote state transportation department spokeswoman Laura Newborn wrote in an emailed statement. “All demolition work over the tracks will take place overnight on weekend hours only, when trains are not running, to ensure the impact to rail operations is minimal.”
BNSF spokesman Gus Melonas says the railroad, contractor, and the state are working out times for demolition.
The transportation department’s website on the project that both the tracks and the steep slope up to the market and Victor Steinbrueck Park “complicate this area, requiring a slower method of removal” involving sawcutting girders and removing them by crane.
Work in that segment is expected to start in late February and be done by early April.
The overall demolition project is expected to take six months.
