Future Boeing Access Road Station moves to East Marginal Way

On March 13, Sound Transit staff recommended the East Marginal Way location for the Boeing Access Road infill station rather than the originally planned location between I-5 and Sounder tracks next to the South Boeing Access Road overpass. Sound Transit held an open house in late February and reviewed both possible locations with the community.

The Boeing Access Road station was included in the 1996 Sound Move Plan but was not authorized by voters until ST3 passed in 2016.ST3 promised the station with 300 parking stalls, which is about half of the parking at Tukwila International Boulevard Station.Besides the platform and parking lot, the station will include two bus bays, a kiss & ride" drop-off zone, as well as space for other drop off services such as Metro Flex or private employer shuttles.The targeted opening date is in 2031.

Locations considered for the Boeing Access Road Station (Sound Transit). Sound Transit staff have recommended a location on East Marginal Way near South 112th Street. Details from the Open House

Sound Transit staff indicated a straight section of track was the key determiner for where station can be sited.In addition to the station itself ST plans to add a crossover track near this station to reduce the distance trains would need to single track during construction of the station.Currently the two closest crossover points are immediately south of Rainier Beach Station and above South 133rd Street (a distance of about 3.2 miles).

Two alternatives were presented at the open house but both would build an elevated station with side platforms and a 300-stall surface parking lot.Sound Transit expects the existing columns and trackways would not be significantly modified beyond the addition of platforms and crossover tracks, eliminating the possibility of a center platform station.Though Sound Move included new Sounder station with transfer connections to Link, the idea is no longer on the table and was deprecated at least as early as 2001.However that does not preclude the spot from becoming a significant bus-rail transfer point, though whether or not Metro or ST decide to truncate south-end express service will be a decision for a much later date.

Detail of the two station locations presented at the Open House (Sound Transit).

The S Boeing Access Road location would have placed the station at the tracks immediately south of Boeing Access Road sandwiched between I-5 and the BNSF tracks.Due to the steep slope at the site ST noted that the tracks are quite high up from ground level, which means a mezzanine level would be required.In addition, the slope may preclude bus access to the station plaza requiring buses to make in-lane stops on Boeing Access Road.

The E Marginal Way location is on East Marginal Way South just north of South 112th Street.ST will need to acquire some nearby businesses in order to build the station and the associated parking.In addition, ST expects to shift Marginal slightly east so that the platform would not be cantilevered over the roadway.An existing traction power substation for Link is at the location of this alternative, so moving it or building around it is be required.This alternative is slightly closer for residents of the Allentown neighborhood.

A third alternative at an undisclosed station was determined to be infeasible and had already been thrown out.

The walkshed for each is rather unimpressive, consisting primarily of industrial and light manufacturing.Both are in reasonable proximity to the nearby Green River trail, and this project of course includes a sizable budget to improve access to the immediate vicinity to the station.The most notable nearby attraction is the Museum of Flight, which is just over a mile away regardless of alternative.

The Q&A portion of the presentation contained predictable concerns predominately related to parking and station access.The majority of the feedback regarding parking was that there was not enough; ST dismissed building a parking garage since its cost would be several orders of magnitude larger than a surface lot, and noted that demand for parking at this station and Tukwila International Boulevard would soften once the thousands of stalls along Federal Way Link come online.A minority expressed disdain at the inclusion of such a large amount of parking, noting that housing or other destination attractions could be built at the site instead.ST countered that building a surface lot instead of a garage allows for more flexibility in converting the site's uses in the future, and is currently interested in fulfilling the promise made to voters in ST3.

With only 300 stalls and staggered arrival and departure times for each car ST doesn't expect significant traffic disruptions to the immediate vicinity, though neighbors questioned several specific nearby intersections.

ST intends to spend a great deal of time soliciting community feedback about the station siting, design, and access. This includes settling on a permanent name for the station, and staff seemed eager to ditch the working name of Boeing Access Road Station".

Getting to the StationThe proposed East Marginal Way station site is about 1,000 feet west of the Route 124 bus stops on Tukwila International Boulevard (Google Maps).

The East Marginal Way location allows for moderately better bus transfers. King County Route 124 runs along Tukwila International Boulevard and riders would have to walk about 1,000 feet along South 112th Street to reach the new infill station. Sound Transit mentioned it plans to install a new traffic signal, which will likely be installed at the intersection of S 112th Street and E Marginal Way S to allow transit riders to cross the East Marginal Way.

Boeing Access Road Station Site Access Plan (1999). Photo by Oran Viriyincy.

The original Boeing Access Road design would have allowed for easy transfers with an new, integrated Sounder station and a transit loop. The original plans from 1999 (shown above) included a pedestrian bridge connecting to an new Sounder station as well as possibly Route 124 terminating at the station. As the East Marginal Way location was selected, transfers to any future Sounder station will instead require at least 3,000 feet (0.6 miles) of walking to the nearest point at which a new Sounder station could feasibly be built, compared to virtually no walk with the original site. This walk could be made shorter but it would require a significant land acquisition and a long pedestrian bridge.Such a station is unlikely to come to fruition without Sounder's popularity booming significantly, and more importantly, its frequency increasing enough to make transferring worthwhile.

Preferred Location and Next StepsSound Transit staff's summary comparison of the two locations considered for the Boeing Access Road station (Sound Transit)

After hearing from community at the Open House in February, Sound Transit staff finished their alternatives analysis and presented their findings at the March 13 System Expansion Committee meeting. Staff recommended the E Marginal Way location since the site is easier to build and provides easier bus transfers.The Sound Transit Board of Directors approved the preferred location yesterday and ST staff will begin formal environmental review and conceptual engineering.

In their recommendation summary, ST staff noted the original station location was evaluated in the Central Link Final Environmental Impact Study in 1999 so they will need to work with the Federal Transit Administration to determine what additional environmental reviews are needed. Preliminary engineering and environmental reviews are expected to be finished early next year and design details finished about two years later. In 2028 construction of the crossover tracks should begin, lasting about a year.From there station construction can commence, with a targeted2031 opening date. The project is estimated to cost $267 million (in 2024$).

Wesley Lin contributed to this report.

Further Reading

• Sound Transit System Expansion Committee Motion M2025-14
• Sound Transit Boeing Access Road Station Project Page
• Sound Transit Staff presentation on the Graham Street and Boeing Access Road Infill Stations, March 13, 2025