PROPOSED SEATTLE LIGHT RAIL EXTENSION: UNIVERSITY LINK
by John Niles
In July 2005, Sound Transit defined a new proposed next extension of its Central Link Light Rail, to cost over two billion dollars including interest on debt. The new segment runs about three miles from Pine Street near the Paramount Theater, crossing under I-5, and then traveling in a bored tunnel up to a Capitol Hill Station. From there it continues underground below Montlake and under the Ship Canal to Husky Stadium at the southeast corner of the University of Washington campus as a temporary northern terminus.
On the map at left, the new segment is the southern half of the full line to Northgate from downtown Seattle that is depicted. University Link goes between Westlake Center and a University of Washington station on the SE corner of the campus. The northern half of the line through two more stations to Northgate is unfunded, but is contemplated as part of the Sound Transit Phase 2 tax increase vote in November 2007 or later..
While the new University Link segment was planned earlier to reach two stations before reaching U of W, it now goes to only one -- on Broadway, the main commercial district on Capitol Hill. The former First Hill Station has been dropped as too difficult and expensive to construct.
Capitol Hill Seattle Blog reports that there are layers of sand under Capitol Hill similar to the ones under Beacon Hill that led to post-construction voids that required filling from the surface above that completed tunnel. The geotechnical report detailing soil conditions along the route of the future University Link subway tunnel is a 14 megabyte pdf. This document contains detailed drawings indicating which surface properties have sand underneath them through which the twin subway tunnels must pass.
Because of the energy consumed by extensive tunnel construction, the Environmental Impact Statement reveals that the construction of the entire northern segment will consume more energy than will be paid back in a lifetime of energy conservation from people riding the train. Why so much energy to construct this? Over 100 thousand truck loads of tunnel dirt will be removed from the Capitol Hill and University of Washington station construction sites while building this project.
Some of the paperwork submitted by Sound Transit to the Federal Transit Administration to justify the "highly recommended" initial ranking for this project is available here for download.
Technical detail excerpted from the New Starts ranking submission on the cost-benefit justification that is calculated using SUMMIT software required by the Federal Transit Administration (300 kilobyte PDF)
Sound Transit has released site plans for the Capitol Hill (Broadway) and University of Washington (Husky Stadium) light rail stations:
Technical report from Puget Sound Transit Consultants to Sound Transit on light rail vibration analysis for North Link Light Rail under University of Washington campus. Executive Summary. Full Report.
Technical report from Sound Transit's consultants LTK Engineering on electro-magnetic field analysis for North Link Light Rail under University of Washington campus. Executive Summary. Full Report.
It is the position of Coalition for Effective Transportation Alternatives (CETA) that this tunneled segment of light rail would be unnecessary if available all-bus alternatives were instead implemented.
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Last modified: February 07, 2011