Last week, the Elected Leadership Group (ELG) for the Ballard and West Seattle light rail extensions received an update from Sound Transit staff on the Chinatown-International District segment. Staff highlighted what they have heard from community and the pros and cons of different station and tunnel options in the neighborhood.

Community feedback on a new station

What community has said about station priorities for Chinatown-International District. (Sound Transit)
What community has said about station priorities for Chinatown-International District. (Sound Transit)

There were several recurring themes from community members that Sound Transit heard on another Chinatown-International District station. Themes like improving connections across transit modes, minimizing impacts to the neighborhood, activating Union Station, and contributing to the community vision.

The community also has indicated a strong preference to rename the light rail stations as “Chinatown-International District”, activating streets around the station, creating more green and open spaces, adding public restrooms and culturally-relevant public art, and facilitating markets and local vendors. Several transit functions that the community has expressed support for include better pedestrian access across 4th Ave S and 5th Ave S and a shallow station for accessibility.

Station and tunnel construction options

The general options to put a new tunnel and station in Chinatown. (City of Seattle)
The general options to put a new tunnel and station in Chinatown. (City of Seattle)

The ELG has some critical issues to consider when it comes deciding upon station and tunnel construction options. Time, cost, constructibility risk and rider convenience are all major factors. To date, Sound Transit is considering five primary station and tunnel options. These include the baseline alternative presented to voters for a 5th Ave S stacked tunnel and station, two other 5th Ave S alternatives with shallow and deep stations, and two 4th Ave S alternatives shallow and deep stations.

Stacking up the options, it is clear that the shallow station options are favored by Sound Transit. Much of that has to do better transfer for passengers and least construct schedule impacts. The 4th Ave S options also appear to be less favored due to traffic impacts, property impacts (particularly King County Metro’s Ryerson Base), and sheer costs estimated to run between $300 million and $500 million more than the ST3 Representative Project alternative.

Comparison chart of key differentiators between the options. (Sound Transit)
Comparison chart of key differentiators between the options. (Sound Transit)

With the key considerations in mind, it seems that a 5th Ave S option may be a better approach for riders and system expansion in general. However, the construction impacts to local businesses and residents in Chinatown could be acute if not heavily mitigated in any 5th Ave S shallow station/tunnel option. The neighborhood has been subject to several major infrastructure projects over the years that have been disruptive to commerce and daily life. It is no surprise then that the community is highly concerned about this and it is something that Sound Transit will need to work on regardless of which option is ultimately chosen.

ST3 Representative Project station and tunnel alternative

Schematic of the 5th Ave S ST3 Representative Project shallow station, construction time, detours, and impacts. (Sound Transit)
Schematic of the 5th Ave S ST3 Representative Project shallow station, construction time, detours, and impacts. (Sound Transit)

The baseline option is the ST3 Representative Project alternative that involves construction of a cut-and-cover tunnel along 5th Ave S and station directly east of International District/Chinatown Station. The station would be located wholly within the 5th Ave S right-of-way and involve a stacked station approach.

A mezzanine would be located just below 5th Ave S to provide for the normal station features like ticket vending machines, wayfinding, and ORCA card readers. It is not clear if the mezzanine would have direct connection to the east platform of International District/Chinatown Station. The overall area of disruption would stretch from Main Street to S Dearborn St. Construction time for the station and tunnel would take about seven years. Detours would last a year-and-a-half.

5th Ave S station and tunnel alternatives

Schematic of the 5th Ave S shallow station, construction time, detours, and impacts. (Sound Transit)
Schematic of the 5th Ave S shallow station, construction time, detours, and impacts. (Sound Transit)

The 5th Ave S shallow option would involve the construction of a stacked shallow station. A mezzanine level would be located at the level of the existing 5th Ave S station, just to its east. The overall area of disruption would stretch from S Jackson St to just south of S King St. Construction time for the station and tunnel would take about six years and detours would last a mere four months. This option also would cost $200 million less than the baseline ST3 Representative Project alternative.

Schematic of the 5th Ave S deep station, construction time, detours, and impacts. (Sound Transit)
Schematic of the 5th Ave S deep station, construction time, detours, and impacts. (Sound Transit)

The 5th Ave S deep station option would involve construction of a deep bored tunnel to avoid some of the local challenges of a shallow station. A mezzanine level would be below the level of the existing 5th Ave S station, which would allow easy transfers to platforms between the stations. The overall area of disruption would be fairly minimal. Construction time for the station and tunnel would take about seven years, but this option would not require any detours. This option would cost also about the same as the baseline ST3 Representative Project alternative.

Transfer times for the 5th Ave S station options. (Sound Transit)
Transfer times for the 5th Ave S station options. (Sound Transit)

According to Sound Transit’s analysis, the shallow station option would perform the best in terms of transfer times. Switching between platforms at the existing International District/Chinatown Station and the new ones would take about one minute. Reaching King Street Station would take about four minutes. Presumably, connecting to buses and the streetcars would take about two to three minutes. Conversely, the deep station option would take five to seven minutes for connections.

4th Ave S station and tunnel alternatives

Schematic of the 4th Ave S shallow station, construction time, detours, and impacts. (Sound Transit)
Schematic of the 4th Ave S shallow station, construction time, detours, and impacts. (Sound Transit)

The 4th Ave S shallow station option allows for platforms at the same level since there is more right-of-way width on 4th Ave S to work within. A mezzanine level would be below the level of the existing 5th Ave S station, which would allow easy transfers to platforms between the stations, and run underneath Union Station. This presumably would allow for integration into Union Station, too, with access to the main floor and street from it.

The overall area of disruption would be extensive, stretching from Main Street to just south of S Lane St. This would require demolition of the 4th Ave S viaduct and full rebuild. The disruptions would occur sequentially over the construction period, requiring half of 4th Ave S to be closed at a time during construction. Construction time for the station and tunnel would take about 10 years and detours would last seven-and-a-half years. This option would also cost about $300 million more than the baseline ST3 Representative Project alternative.

Schematic of the 4th Ave S deep station, construction time, detours, and impacts. (Sound Transit)
Schematic of the 4th Ave S deep station, construction time, detours, and impacts. (Sound Transit)

The 4th Ave S deep station option would involve construction of a deep bored tunnel to avoid some of the local challenges of a shallow station. Similar to the other 4th Ave S option, a mezzanine level would be below the level of the existing 5th Ave S station, which would allow easy transfers to platforms between the stations, and run underneath Union Station.

The overall area of disruption would be somewhat extensive, stretching from S Jackson St to S Lane St. Disruption under this option, however, would require full closure along the entirety of 4th Ave S. Construction time for the station and tunnel would take about nine years and detours would last five years. This option would also cost about $500 million more than the baseline ST3 Representative Project alternative.

Transfer times for the 4th Ave S station options. (Sound Transit)
Transfer times for the 4th Ave S station options. (Sound Transit)

According to Sound Transit’s analysis, the shallow station option would perform the best in terms of transfer times. Switching between platforms at the existing International District/Chinatown Station and the new ones would take about four minutes. Reaching King Street Station would also take about four minutes. Presumably, connecting to buses and the streetcar would take about two to three minutes. Conversely, the deep station option would take five to seven minutes for connections.

Points of clarification

During the meeting, Seattle Councilmember M. Lorena González asked Cathal Ridge, a program manager for Sound Transit, to clarify what the construction duration estimates meant. Mr. Ridge explained that the estimates indicate Sound Transit’s time to construct the options, but would not likely impact the date of light rail opening. Instead, it means construction would have to begin earlier in the expansion process for options that have longer durations.

Major projects intersecting with the station area. (Sound Transit)
Major projects intersecting with the station area. (Sound Transit)

Sloan Dawson, a Sound Transit urban designer, introduced the concept of the Jackson Hub, which would bring more prominence to the stations and transit in the area while also improving the public realm. Seattle Councilmember Mike O’Brien followed to ask what sort of transit hubs that Sound Transit is looking at for inspiration to create a more dynamic and functional multimodal hub.

“One of the off-site precedents for the kind of vision Jackson Hub presents is Denver’s Union Station, an example of having an activated commercial area,” Dawson said. “[We’re] really thinking about the development that is integrated into the transit function, but also really centering the station itself as kind of a public asset or park almost.”

Next steps

In two weeks, the Stakeholders Advisory Group will make Level 3 screening recommendations on the Ballard and West Seattle light rail extensions. The ELG would make their own Level 3 recommendations at the end of the month. The Sound Transit Board of Directors will then take up discussion on a preferred alternative and other alternatives to take into the environmental review process in early May. A final decision on alternatives to be study will be made by the board of directors on May 23rd.

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2 COMMENTS

  1. The 5th Ave Shallow station is most performant, and is the cheapest. I think this is the clear best option, plus we’d have $200M left over to improve the other lines or put towards other projects as appropriate

  2. It seems obvious. Take the four month detour, throw a bunch of cash at any affected business owners to appease them, and build the shallow station. Build it as quick as possible! The city needs it now!

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