East Link's B2M & C9T/C11A Preferred Alternatives. 112th Ave is under the red highlight..

Last Thursday, the Sound Transit Board heard a report (PDF) on the varying options that have been studied for East Link’s B and C segments.  In April, the Board’s go-ahead with the 112th Ave/B2M segment (see image above) accelerated the alignment into preliminary engineering.  The Board also chose two downtown preferred alternatives: C9T, a tunnel, and C11A, a surface alternative in the event of inadequate funds for the tunnel.  For those unfamiliar with the storied history of East Link planning, the B2M alternative is the most direct path to the Bellevue Transit Center, but because runs so close to neighborhoods, has been targeted acutely by NIMBY residents in South Bellevue.

The report given on Thursday was heavy on how a 112th Avenue alignment could work with “community interests.”  Six options were studied which mix-and-matched various 112th Ave modifications (at-grade, side-running, center-running, etc.) with the downtown C segment options, the C9T tunnel and the C11A surface alignment.  A brief rundown of the options before I get to my scatterbrained thoughts:

More below the jump.

Options 1 & 2 run the 112th Ave segment to the downtown tunnel with its southern portal at Main Street.  The first has trains center-running along 112th, while the second has them running west-side.  Because trains need to curve west into the tunnel portal, a more indirect east-side running option was not considered.

Options 1 & 2 (click to enlarge)

Options 3 & 4 run the 112th Ave segment to the downtown tunnel with its southern portal further north at 2nd Street, meaning a shorter tunnel.  Option 3 would have trains center-running all the way up 112th to the portal, while Option 4 would have the trains running east-side in a trench/retained cut.  The east-side running option was considered here because the 2nd Street portal does not require as tight a turn into the tunnel.  The west-side option was nixed due to building setbacks being much wider on the east side of the street with less property condemnations.  Buildings on the west-side, however, go up right to the street.

Options 3 & 4 (click to enlarge)

Options 5 & 6 run trains from the B segment to the C11A surface alignment, with 5 center-running and 6 west-side running.  An east-side option wasn’t considered for the same reason as Options 1 & 2.

Options 5 & 6 (click to enlarge)

While you can view the CH2M Hill report and analysis in its entirety (PDF), there are a few thoughts about what might be feasible.:

Any option that either runs the trains center through 112th  or on the west-side is bound to be unpopular among most South Bellevue residents given the “preserve homes and roads” mantra.  Bellevue is also heavily pro-tunnel, meaning that Options 5 & 6 likely do not fare well, despite yielding the greatest cost reductions.

I would surmise that Option 4 would pique the most interest due to: a shorter and cheaper tunnel, wide setbacks east of 112th allowing for right-of-way to minimize property displacements, and mitigated noise impacts thanks to the trench.  Downsides include longest construction duration and most environmental impacts within the wetland buffer (but not the wetland itself).  However, among the issues that seem most politically important to Bellevue, Option 4 seems most likely to shine the brightest.

Bellevue's preferred alternative: B7 & C9T

Keep in mind that while Sound Transit and the City have ostensibly surged forward with the B2M options, there are several camps that have been steadfast to tauting B7 as the better alternative, which would run trains around South Bellevue and Mercer Slough and alongside the freeway.  In February, we openly condemned B7 as an inadequate choice for East Link.  At a workshop (PDF) on June 15th, the first of three, ST invited community members and residents to discuss the B2M/112th options.  Turnout among B7 supporters was apparent, however.  Martin Paquette, an occasional STB commenter, had this small synopsis:

Tonight’s workshop was civilized, and it appeared that a large amount of discussion occurred that related to the best ways to accomplish B2M along 112th Avenue.  There were a huge lot of persons who were wearing B7 stickers, but they weren’t blowing tremendously loud horns; rather, they let Sound Transit get its job done.  Nevertheless, there were no visible persons who were against B7.

From another report at the same workshop, we also learned a little more about Option 4’s retained cut/trench and its impacts on the Bellevue Club, which would have to lose some land for the right-of-way.  Among the concerns were the loss of a few of the club’s tennis courts, little room for landscaping along 112th Ave, and an aesthetically unappealing suicide net that would be placed over the trench.

As previously mentioned, there will be two more workshops (one of which is tonight), and an open house on July 14th.  We’ll keep you updated as ST and City move to choose an option for this segment of East Link.

21 Replies to “Design Options for East Link through Bellevue”

    1. The main difference is that a lidded trench is not fully enclosed while a cut-and-cover tunnel is. Take a look at some of the old concepts for the AW Viaduct replacement, specifically options G & H.

  1. Building in a wetland just seems like a terrible idea. There is a reason that these wetland buffers are kept.
    And we’re never going to get that open space back if we give it up now. There’s plenty of ROW on 112th for the train, without having to rob the Mercer Slough.

  2. I still don’t understand the SE 8th station. Is there *any* potential for upzoning in that area? This station seems to be the ultimate in “Build it and they will come” transit planning. Same goes for many of the stations in the C segment, but at least Bellevue has pretty detailed plans to upzone that area and increase density.

    1. West of 112th at SE 8th will always remain SF-residential, Surrey Downs or not. East of has more potential because the Residence Inn was recently built a block over on 114th. I’m not sure what future prospects would be, given that Surrey Downs would probably consider upzoning on that plat encroachment on the neighborhood’s single-family character. Ironically, it’s already exactly like that at Main Street, the southern edge of downtown. I could get in touch with Paul Ingraham, a planning head at the Bellevue office, to see what the City might be considering there.

  3. Option 2 has A LOT of property condemnations. You can take a look here: http://projects.soundtransit.org/Documents/pdf/projects/eastlink/112th_2010/112thAvenueLRToptionspresentation_62410.pdf on page 13 to see for yourself, and compare to the other options. If you go down further in the presentation you can see that all of the options have some impact to the wetland buffer area as well as to park areas, while none impact actual wetland. Option 4 is the obvious choice for the long run as its grade separation would not limit future capacity and would encourage more use of the line by residents living near other portions as said grade separation would decrease travel times compared to the other options. This does not include other benefits which include the least noise impacts, the least property acquisitions, as well as affecting the second least amount of park acreage. Also, if you flip through the renderings on that presentation, you can see that only the options which include westside running do not result in the Bellevue Club loosing a tennis court or two. I think that if the choice comes down to the Bellevue Club loosing some tennis courts or 46 residences and 7 businesses being displaced, the choice should be obvious.

    1. It still has a grade crossing at SE 8th, so that will limit its capacity along with the crossings in the Bel-Red area. If only they got rid of the SE 8th crossing, we could imagine a future Kirkland extension that had trains run into Seattle or onto some other extension toward Renton or Issaquah.

      1. It’s a little bit of a stretch to say that eliminating one crossing will bring a Kirkland extension into reality.

      2. Not make it a reality, that would require funding the extensions. But having one crossing with a major street does limit the train frequency to about the minimum you really want to limit a line like this. Basically the trains between Seattle and Redmond will be limited to 6 minute headways, and 3 things prevent that from being increased: the need to leave room for SeaTac trains in the downtown Seattle tunnel, the grade crossing at SE 8th, and the grade crossings east of Overlake Hospital Station. Eliminate the SE 8th crossing, and you can add another line with 6 minute headways to this section of the track, making something like Kirkland-Issaquah a feasible phase 3 plan with shared tracks between south Bellevue and Overlake Hospital. If you’re going to go almost far enough to allow this, we should really consider eliminating this last crossing to improve our phase 3 options.

  4. I’m not sure I get why all the tunnel alignments put the station at 110th rather than 108th. Is it just the cost of an extra 1/4 mile of tunnel? Seems you’d want to get a little further into Bellevue.

    1. The ST board has already selected the 110th Ave alignments as the preferred alignments. The study was just looking at options for connecting into C9T or C11A.

      1. Right, want to remind me why 110th was preferred? I assume it’s cost, but how much cost difference roughly?

      2. So trains don’t have to cross NE 8th in Downtown, plus the 110th alignment will lead to the Wilburton and Overlake Hospital area, where the city is planning some sort of massive redevelopment

      3. So basically they don’t want to tunnel under the Bellevue Transit Center? I assume these are cut-and-cover tunnels then? And continuing north on 108th would mean an especially long tunnel (too expensive) or a surface crossing of 8th (too disruptive).

      4. C9T (under 110th Ave NE) is a cut&cover tunnel. The original tunnel alternative, C3T under 108th Ave NE is a bored tunnel.

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