Galer Street Station/Central Interbay Alternative (preferred alternative)

The Galer Street Station/Central Interbay Alternative would continue the tunnel beneath Republican Street in the Downtown segment from 2nd Avenue West to a tunnel portal on the east side of 5th Avenue West. From the tunnel portal, the alternative would become elevated and cross to the west side of Elliott Avenue West and continue northwest. The guideway would cross to the east side of Elliott Avenue West near West Mercer Place and would continue northwest between the east side of Elliott Avenue West and Kinnear Park. North of Kinnear Park, the alignment would transition to the west side of Elliott Avenue West to enter the Smith Cove Station. Smith Cove Station would be elevated above the West Galer Street bridge. From the Smith Cove Station, the elevated guideway would cross over the Magnolia Bridge and continue north along the east side of the BNSF Railway tracks to West Armory Way. From West Armory Way, the alignment would continue north along the western edge of the Interbay Golf Center and Interbay Athletic Complex. The elevated guideway would continue over West Dravus Street and connect to the Elevated 14th Avenue Alternative in the Interbay/Ballard segment. For this alternative to connect to the tunnel alternatives (Tunnel 14th Avenue Alternative and Tunnel 15th Avenue Station Option) in the Interbay/Ballard segment, it would transition from elevated to at-grade along the Interbay Athletic Complex to continue under West Dravus Street.

Prospect Street Station/15th Avenue Alternative (other DEIS alternative)

The Prospect Street Station/15th Avenue Alternative would continue the tunnel beneath Republican Street in the Downtown segment from 2nd Avenue West to a tunnel portal on the east side of 5th Avenue West. From the tunnel portal, the alternative would become elevated and cross to the west side of Elliott Avenue West and continue northwest. The guideway would cross to the east side of Elliott Avenue West near West Mercer Place and would continue northwest between the east side of Elliott Avenue West and Kinnear Park. It would enter an elevated Smith Cove Station north of Kinnear Park on the east side of Elliott Avenue West. The station would be north of West Prospect Street. From the Smith Cove Station, the elevated guideway would continue northwest along the east side of Elliott Avenue West and then transition to a retained cut along the edge of the Southwest Queen Anne Greenbelt before turning north and transitioning to the center of 15th Avenue West near West Newton Street. It would continue on the elevated guideway in the middle of 15th Avenue West to West Barrett Street. This alternative would only connect to the bridge alternatives (Elevated 14th Avenue Alternative Alignment Option and Elevated 15th Avenue Alternative in the Interbay/Ballard segment).

Prospect Street Station/Central Interbay Alternative (other DEIS alternative)

The Prospect Street Station/Central Interbay Alternative would continue the tunnel under West Mercer Street from the Downtown segment from 2nd Avenue West to a tunnel portal east of Elliott Avenue West on the northwestern edge of Kinnear Park, south of West Prospect Street. The alternative would continue north from the tunnel portal in a retained cut to Smith Cove Station north of West Prospect Street. The station would be in a retained cut, and the alternative would continue north in a retained cut along the edge of the Southwest Queen Anne Greenbelt. The alternative would transition to an elevated guideway near West Howe Street and cross 15th Avenue West at West Armory Way to travel northwest along the northern side of West Armory Way. From West Armory Way, it would continue north along the western edge of the Interbay Golf Center and Interbay Athletic Complex and then continue over West Dravus Street to connect to the Elevated 14th Avenue Alternative. For this alternative to connect to the tunnel alternatives (Tunnel 14th Avenue Alternative and Tunnel 15th Avenue Station Option) in the Interbay/Ballard segment, it would transition from elevated to at-grade along the Interbay Athletic Complex and continue under West Dravus Street.

5th Avenue/Harrison Street Alternative (preferred alternative)

The 5th Avenue/Harrison Street Alternative would be in a tunnel generally from south heading north under 5th Avenue and Westlake Avenue and then heading west under Harrison Street and Republican Street. Stations would be located as follows:

• Midtown Station: The station would be beneath 5th Avenue between Columbia Street and Madison Street.
• Westlake Station: The station would be beneath 5th Avenue between Pike Street and Pine Street.
• Denny Station: The station would be beneath Westlake Avenue between Denny Way and Lenora Street.
• South Lake Union Station: The station would be beneath Harrison Street, between Dexter Avenue North and just west of Aurora Avenue North.
• Seattle Center Station: The station would be beneath Republican Street, east of 1st Avenue North.

6th Avenue/Mercer Street Alternative (other DEIS alternative)

The 6th Avenue/Mercer Street Alternative would be in a tunnel generally from south heading north under 6th Avenue and Terry Avenue, and then west under Mercer Street. Stations would be located as follows:

• Midtown Station: The station would be beneath 6th Avenue, between Madison Street and Seneca Street.
• Westlake Station: The station would be beneath 6th Avenue, between Pine Street and Olive Way.
• Denny Station: The station would be beneath Terry Avenue North, between Denny Way and John Street.
• South Lake Union Station: The station would be north of Mercer Street between Aurora Avenue North and Taylor Avenue North.
• Seattle Center Station: The station would be beneath Mercer Street, between Warren Avenue North and Queen Anne Avenue North.

4th Avenue Shallow Alternative

The 4th Avenue Shallow Alternative would begin at-grade in the vicinity of South Holgate Street, east of the existing Link light rail line, and extend north. The alternative would enter a tunnel between Edgar Martinez Drive South and South Royal Brougham Way. The tunnel would continue to the northwest under the existing Link light rail line at South Royal Brougham Way and then north under 4th Avenue South. A new station in the Chinatown-International District would be under 4th Avenue South, west of the existing Chinatown-International District Station. The 4th Avenue South Viaduct would be demolished and reconstructed to accommodate construction of this station.

4th Avenue Deep Station Option

The 4th Avenue Deep Station Option would begin at-grade in the vicinity of South Holgate Street, east of the existing Link light rail line, and extend north. The tunnel portal would be in the vicinity of South Massachusetts Street and the tunnel alignment would begin transitioning to follow 4th Avenue South farther south than the 4th Avenue Shallow Alternative. From Seattle Boulevard South to James Street, the alignment and station location would be similar to the 4th Avenue Shallow Alternative but would be deeper.

5th Avenue Shallow Alternative

The 5th Avenue Shallow Alternative would begin at-grade in the vicinity of South Holgate Street, east of the existing Link light rail line, and extend north. The alternative would enter a tunnel in the vicinity of South Massachusetts Street and would continue north beneath 6th Avenue South. The tunnel would transition to be under 5th Avenue South north of Seattle Boulevard South. The station in the Chinatown-International District would be under 5th Avenue South, east of the existing Chinatown-International District Station. 

5th Avenue Shallow Diagonal Station Configuration

The 5th Avenue Shallow Diagonal Station Configuration would be the same as the 5th Avenue Shallow Alternative except that it would transition towards 5th Avenue South further north of Seattle Boulevard South with a similar station entrance location.

5th Avenue Deep Station Option

The 5th Avenue Deep Station Option would generally follow the same route as the 5th Avenue Shallow Alternative, except that the tunnel and the station would be deeper.

At-Grade Alternative (preferred alternative)

The At-Grade Alternative would travel at-grade west of and parallel to the existing Link light rail line in the SODO Busway. It would travel under the new South Holgate Street overpass, resulting in grade separation of vehicular traffic. The SODO Station would be at-grade, immediately west of the existing SODO Station, north of South Lander Street. This alternative would continue south at-grade under South Lander Street, which would be reconstructed as an overpass of the light rail tracks, resulting in grade separation from vehicular traffic. The light rail would transition to an elevated guideway along the SODO Busway south of South Lander Street.

At-Grade Staggered Station Configuration (preferred alternative)

The At-Grade Staggered Station Configuration would be the same as the At-Grade Alternative (preferred alternative) except that the west platform would be shifted slightly to the north. It would have the same station entrance locations.

At-Grade South Station Option (other DEIS alternative)

The At-Grade South Station Option would generally be the same as the preferred alternative, except for the SODO Station location. A new at-grade station would be west of and approximately 200 feet south of the existing SODO Station, just north of South Lander Street. The existing SODO Station would also be relocated 200 feet south of its current location to be next to the new SODO Station.

Mixed-Profile Alternative (other DEIS alternative)

The Mixed-Profile Alternative would travel at-grade north of the existing SODO Station, west of and parallel to the existing Link light rail line in the SODO Busway. South Holgate Street would be constructed as a new roadway overcrossing, resulting in grade separation with vehicular traffic. At South Walker Street, the alignment would transition to an elevated guideway and would continue south over South Lander Street. A new SODO Station would be elevated north of South Lander Street. This alternative would be elevated over South Lander Street, with a gated at-grade crossing of the existing light rail line, similar to today’s condition. The existing SODO Station would be relocated as described for At-Grade South Station Option and would be at-grade adjacent to the new elevated station.

Elevated 41st/42nd Avenue Alternative (preferred alternative)

The Elevated 41st/42nd Avenue Alternative would be elevated along the south side of Southwest Genesee Street between 31st Avenue Southwest and Fauntleroy Way Southwest. The alternative would turn southwest and continue along the north side of Fauntleroy Way Southwest before curving southwest between Southwest Oregon Street and Southwest Alaska Street. The guideway would turn south in the vicinity of 41st Avenue Southwest and Southwest Alaska Street and continue south to Southwest Hudson Street. The guideway would end on the west side of 42nd Avenue Southwest and would include a tail track south of the West Seattle Station. Stations would be located as follows:

• Avalon Station: The station would be elevated along the south side of Southwest Genesee Street, east of 35th Avenue Southwest.
• West Seattle Station: The station would be elevated between 41st Avenue Southwest and 42nd Avenue Southwest, south of Southwest Alaska Street.

Elevated Fauntleroy Way Station Alternative (preferred alternative)

The Elevated Fauntleroy Way Station Alternative would be elevated along the south side of Southwest Genesee Street between 31st Avenue Southwest and Fauntleroy Way Southwest. The alignment would head southwest on Fauntleroy Way Southwest and continue along the west side of Fauntleroy Way Southwest. The guideway would cross to the east side of Fauntleroy Way Southwest south of Southwest Oregon Street. Elevated tail tracks would begin south of the West Seattle Station and end within the Fauntleroy Way Southwest right of way just past Southwest Edmunds Street. Stations would be located as follows:

• Avalon Station: The station would be elevated along the south side of Southwest Genesee Street and east of 35th Avenue Southwest.
• West Seattle Station: The station would be elevated southeast of Fauntleroy Way Southwest, straddling Southwest Alaska Street.

Tunnel 41st Avenue Station Alternative (preferred alternative with third-party funding)

The Tunnel 41st Avenue Station Alternative would be in a tunnel under Southwest Genesee Street heading west from 31st Avenue Southwest then curve to the southwest between 37th Avenue Southwest and 41st Avenue Southwest. The tunnel would end in the vicinity of Southwest Hudson Street, with the tail track in a north-south orientation under 41st Avenue Southwest. The guideway would be entirely in a tunnel. Stations would be located as follows:

• Avalon Station: The station would be beneath Fauntleroy Way Southwest.
• West Seattle Station: The station would be beneath 41st Avenue Southwest and Southwest Alaska Street.

Tunnel 42nd Avenue Station Option (preferred alternative with third-party funding)

The Tunnel 42nd Avenue Station Option would be the same as the Tunnel 41st Avenue Station Alternative, except the tunnel would extend to 42nd Avenue Southwest instead of 41st Avenue Southwest. The tunnel would end in the vicinity of Southwest Hudson Street, with a tail track in a north-south orientation under 42nd Avenue Southwest. The guideway would be entirely in a tunnel. Stations would be located as follows:

• Avalon Station: The station would be the same as described for the Tunnel 41st Avenue Alternative.
• West Seattle Station: The station would be in a tunnel beneath 42nd Avenue Southwest and Southwest Alaska Street.

Short Tunnel 41st Avenue Station Alternative (other DEIS alternative)

The Short Tunnel 41st Avenue Station Alternative would be on an elevated guideway along the south side of Southwest Genesee Street from 31st Avenue Southwest to the west side of Fauntleroy Way Southwest. It would continue along the west side of Fauntleroy Way Southwest on an elevated guideway before transitioning to an at-grade alignment near 37th Avenue Southwest. The guideway would turn west near Southwest Oregon Street and transition into a tunnel with a portal in the vicinity of Southwest Oregon Street and 38th Avenue Southwest. The tunnel would turn south and end south of Southwest Hudson Street, with a tail track in a north-south orientation along and under 41st Avenue Southwest. Stations would be located as follows:

• Avalon Station: The station would be elevated along the south side of Southwest Genesee Street and east of 35th Avenue Southwest.
• West Seattle Station: The station would be in a tunnel beneath 41st Avenue Southwest and south of Southwest Alaska Street.

Medium Tunnel 41st Avenue Station Alternative (other DEIS alternative)

The Medium Tunnel 41st Avenue Station Alternative begins in a retained cut south of Southwest Yancy Street and follows the east side of the West Seattle Bridge connection to Southwest Genesee Street. This alignment enters a tunnel at Southwest Genesee Street and 37th Avenue Southwest. The alignment then curves southwest west of 37th Avenue Southwest to 41st Avenue Southwest. It terminates at Southwest Hudson Street, with the tail track in a north-south orientation under 41st Avenue Southwest. The guideway would be entirely in a tunnel. Stations would be located as follows:

• Avalon Station: The station would be in a retained cut south of Southwest Genesee Street, beneath Fauntleroy Way Southwest.
• West Seattle Station: The station would be in a tunnel beneath 41st Avenue Southwest and Southwest Alaska Street.