ST adds new light rail options to the mix

West Seattle Junction from above (SounderBruce)

At the direction of the Sound Transit board, staff studied several new ST3 alignment options to the same level of design as existing options. They looked at new variants at Delridge, Sodo, and in the core of Ballard. They presented the result to the system expansion committee yesterday.

Delridge

The previous level 3 alternatives all enter West Seattle near the bridge, take a hard left onto Delridge, where there's a station, and then another hard turn onto Genesee and on to Avalon Station. There were both elevated and tunneled options along this path, though the tunnel would require unspecified third-party funding.

The new alignments both reduce "impacts" on the residential communities in that path. One would move the elevated line north, with Delridge Station also being north and the track hugging the steel plant. Executive Corridor Director Cathal Ridge says this alignment also precludes a tunnel to Alaska junction, but is cost-neutral relative to the baseline.

Sound Transit

The other tunnels under Pigeon Point and must feed into a tunnel to the Junction. The Delridge station would be further south. The Pigeon Point tunnel would add another $200m, and paired with the junction tunnel the added cost would be $900m. The combined tunnels would likely delay this segment's arrival by "years."

The study spills a lot of ink on construction impacts, views, and so on. But what's better for riders? At this level of precision, ST doesn't see any difference in ridership. The northern alignment is a little curvier, and the tunneled route a bit straighter and flatter, which both may have very small travel time impacts. The southernmost Delridge station is a bit better for transfers from buses, but it's hard to see $900m of benefit there.

Sodo

The status quo plan has both lines running at grade, with new overpasses at Lander and Holgate Streets. Thus, only at Royal Brougham would trains have to interface with traffic.* On the other hand, there wouldn't be room to continue the Sodo busway.

The new alternatives elevate one or both of the lines. Elevating both costs an extra $300m and requires two multi-month closures of the Rainier Valley line. First, they would build the West Seattle elevated segment, switch Rainier Valley line onto it during the first closure, and then replace the existing track with an elevated West Seattle line. This creates room to keep the busway and simplifies some transfers, but it costs money and the closure is a big obstacle.

The "partial elevated" option would only elevate the new track, and doesn't cost any more. However, it would eliminate the overpass and Lander Street, introducing another traffic crossing. Local businesses are concerned that a new Lander overpass would be as disruptive as the building the current one. Partial elevated also retains room for a busway.

In truth, these options will at best maintain rider experience compared to the current plan, while also imposing large costs in the budget and in service disruption.

Ballard

The Ballard study tried to find a way to put a station at 20th Ave, the heart of Ballard, to go with a slew of existing options on 14th and 15th. The tunneled alignment the board proposed would cost an additional $750m over an elevated line to 14th or 15th, and creates some challenges around the BNSF tracks.

Not satisfied, staff explored an alignment that comes closer to the Ballard Bridge, which reduces the cost by $300m. (!) The track is straighter, leaving room for a crossover without digging further up 20th to install one.

Interestingly, the admittedly coarse ridership analysis didn't find much difference between 20th and 15th Avenue stations. While 20th has a better walkshed, this terminus station is expected to draw a lot of buses that will have a harder time getting over to 20th. These more or less cancel each other out. Guest writer Dale Menchoffer saw this differently in March, but judge for yourself.

Conclusion

Sound Transit will make a decision that pleases many stakeholders, many of whom care little about convenience to riders in 2035 and a lot about noise and traffic disruption both during and after construction. This is inevitable, but shortsighted.

Taking the long view, the new West Seattle options make things strictly worse or infinitesimally better at high opportunity cost. The Sodo options achieve little but for easing neighbor concerns about vehicle flow. The Ballard tunnel offers some intriguing improvements at medium cost, trading off the interests of residents of old Ballard, and people trying to get there, against people further afield just trying to get downtown.

I asked Mr. Ridge how long Sound Transit could wait for stakeholders to assemble a funding plan before it started to impact the schedule. He said that they would need at least a detailed funding plan by the end of 2020 when the Board picks a single preferred alternative, and for the funding to be firmly in place by mid-2022. The window for ST3 add-ons is apparently wide enough for Seattle's next TBD vote, but perhaps a little too narrow to get federal aid out of the next Congress.

* The new alignment will not have a Stadium station as it's already diving underground, and will therefore not cross Royal Brougham. Thanks to the switcheroo, this means the Rainier Valley Line would have zero at-grade crossings through Sodo, and the West Seattle line would have one at Royal Brougham.