By Lizz Giordano

The massive draft environmental impact statement  (DEIS) for the West Seattle-Ballard light rail extension landed on Sound Transit’s website in late January. It lays out the pros and cons of a variety of elevated and tunnel routes as the agency tries to weave light rail tracks through some of the densest parts of Seattle.

This second Seattle light rail line will start at the current SoDo station and cross the Duwamish Waterway before skirting the north edge of the West Seattle Golf Course on its way to the Alaska Junction. The Ballard spur will start in the Chinatown-International District (CID), then head north through a new tunnel under downtown toward Seattle Center, through Interbay, and over or under Salmon Bay to its terminus in Ballard.

This extension will add a second transit tunnel through downtown to handle increased train volumes (including the new extension to Everett, also part of Sound Transit 3) and new stations near existing ones at Westlake, the CID and SoDo, which will become transfer points between the two light rail lines.

Some options offer better bus connections or more potential for transit-oriented development. Other alternatives lessen construction impacts by moving stations to the fringes of the neighborhood or deep below ground.

As the Sound Transit board makes a final decision on the route, expected in 2023, board members will be weighing short-term construction impacts against building a system that’s easy and seamless for riders to use for decades. Those decisions might be a little easier now that the costs of elevated routes is similar to that of tunneling. But underground stations don’t always equal a better experience for riders.

To keep certain tunnel routes on the table for West Seattle and Ballard, as requested by many in those neighborhoods, Sound Transit board members representing King County proposed a last-minute compromise in 2019. It stipulated that while the agency staff would continue to study the more expensive tunnel routes, they would not move forward without third-party (non-Sound Transit) funding.

A few years later, the relentless increase in property values has made it just as expensive to build above ground as to tunnel beneath the city for third-party funding.

In Ballard, where there are basically four options—an elevated or underground station at NW Market Street and either 14th or 15th Ave. NW—the price tag for the elevated options is now almost identical to the estimated cost to tunnel: Between $1.5 billion and $1.6 billion, compared to $1.5 billion to $1.7 billion for the tunnel alternatives.

As the cost difference has evaporated, Seattle Subway, a transit advocacy group, hopes to persuade the agency to revive an old proposed route along 20th Avenue Northwest that would deliver riders closer to the core of the neighborhood rather than several blocks east. Serving dense neighborhoods (rather than more car-centric areas on their periphery) is a core urbanist tenet: High-capacity transit works best when it serves a dense core of riders, and easy access to transit can spur more density in urban areas.

To fully resurrect this option, however, Sound Transit would have to create an entirely new environmental impact statement, which is no easy task and could add time to the project.

If that doesn’t happen, routes along 14th Avenue NW might offer the best combination of transit connections and development potential. The 14th Avenue location provides better transfers between buses and trains than alternatives on 15th Avenue, while also avoiding the need to build a moveable bridge over Salmon Bay.

A buried route along 14th would also create opportunities for transit-oriented development on Sound Transit-owned land after construction—up to 450 housing units and 70,000 gross square feet of retail space. While transit-oriented development is hardly the entire answer to Seattle’s housing crisis, building transit around stations is a must-do; in South Seattle, where Sound Transit failed to plan for housing two decades ago, the sparsely populated light rail line represents a series of missed opportunities.

A similar price convergence is also occurring between above and below ground options in West Seattle, where stations are planned for the Junction, the Avalon area and North Delridge.

While a long-requested tunnel route to preserve views and “neighborhood character” from the West Seattle Golf Course to the Alaska Junction—estimated cost: $1.7 billion—is still much more expensive than the two elevated options, which are priced at $900 million and $1.3 billion, respectively. But a shorter tunnel route that would head below ground after the Avalon Station is now estimated to cost $1.1 billion, less than even one of the above ground routes.

At the Alaska Junction, future transit-oriented development hinges more on the location of the station than on whether the line is elevated or buried. Stations at 41st or 42nd Avenues SW have the potential to create slightly more residential units and commercial space on leftover Sound Transit land than if the station is further east. Any kind of station on 41st Ave.  offers the best bus connection for what will become a terminus station, according to the DEIS.

While laying tracks underground minimizes construction impacts on the surface and usually displaces the fewest businesses and residents, it doesn’t always lead to a better experience for future riders. This is especially true if the journey out of these deep stations or between lines becomes its own leg of the commute.

At the new Westlake Station downtown, Sound Transit plans to bury the train platform 135 feet below the surface regardless of which alternative the board chooses—more than twice the depth of the existing station. The agency estimates it would take most riders three to six minutes to get from the street to the train platform —two escalators or two elevator rides, or a mix of both (plus a stair option on the last leg), according to the agency.

Expect another long ride to the platform at the Midtown Station at Fifth or Sixth Avenue at Madison St. downtown, which is likely to be buried even deeper: Between 140 and 205 feet.

One proposed station in the Chinatown-International District would be 190 feet underground  That’s an estimated 3.5-minute elevator trip to the surface, which could lengthen depending on the size of the crowd waiting at either end. By 2042, not long after the station is set to open, those lines could get quite long during peak hours, with between 30,100 and 34,200 riders expected to board there each day. For comparison, the Beacon Hill Station—also with elevator-only access —is buried about 160 feet underground.

With deep tunnels also come longer transfer times. Westlake, the CID Station, and SoDo will be major transfer points between the lines.

Opportunities for shallower stations are limited, said Rachelle Cunningham, a spokesperson for Sound Transit, due to soil makeup and existing infrastructure.

“We need more explanation from them why it’s so deep,” said Ben Broesamle, with Seattle Subway. “Light rail needs to be competitive with driving, and deep stations just add to the commute time.”

The Chinatown-International District is closely watching the placement of the route as the area faces a messy years-long buildout for the second station built to serve the new light rail extension. The subterranean station could go under Fourth or Fifth Avenue, and Sound Transit is studying both deep (190-foot) and shallow alternatives.

Placing the station under Fourth Ave would lessen the impact to the neighborhood during construction, as opposed to building one block to the east, according to leaders in the CID and Sound Transit.  It would also offer better integration with Sounder and Amtrak trains and with the major bus corridor along the avenue.

However, this option would take the longest and is also the most expensive alternative, because it would require rebuilding a viaduct just east of Centurylink Field, leading to a years-long street closure of the street. On the other hand, rebuilding the viaduct now could save the neighborhood a future mess by replacing the aging infrastructure as part of the light rail project.

Rebuilding the viaduct to accommodate light rail would also narrow the roadway from six to four lanes, according to current plans. This redesign of the wide avenue between Union and King Street stations could be a catalyst for activating the space around the two stations.

While a station on Fifth would make for the quickest transfer between light rail lines, it would also seize some land in the Seattle Chinatown Historic District. One station entrance would be just steps away from the Chinatown Gate, according to the plans.

Sound Transit is accepting comments on the DEIS at WSBLEDEIScomments@soundtransit.org until April 28. The West Seattle segment is set to start operating in 2032, followed by the Ballard route in 2037 or 2039.