Tacoma CC Light Rail means Changes to Tacoma Link Expansion

Tacoma Link Expansion at S. 4th and Stadium Way

Post Highlights:

  • Getting to TCC will require design changes to the planned Tacoma Link Expansion in Final Design
  • Conceptual TCC light rail service would be in its own exclusive right of way, while Tacoma Link Expansion is currently designed to operate in mixed traffic
  • Service to TCC would require replacement of the Tacoma Link fleet with larger vehicles, longer station platforms, and new Northbound track along Puyallup Avenue
  • Takeaway: Usually planning documents affect the future, but in this case, they can also affect current projects still in planning.

On Friday, Sound Transit released analysis documents (available on soundtransit3.org) showing costs and ridership for projects that will eventually form the ST3 ballot measure.

S11: Tacoma Link to TCC concept project along S. 19th St.
S11: Tacoma Link to TCC concept project along S. 19th St.

The purpose of these documents was to provide the Sound Transit Board with the ability to compare competing projects before compiling a draft plan to go out for public comment in early 2016.

Exclusive Right of Way

Included in these documents is S-11, analyzing the Tacoma Link Extension to Tacoma Community College.  Sound Transit utilized S. 19th St as a conceptual corridor in its analysis.  The concept light rail service would operate at grade, but principally in exclusive right of way in the median of a largely reconstructed S. 19th St.  A total of seven stations would be placed at Union Avenue, State St., Proctor St., Stevens St., Ainsworth Ave, S. Pearl, and at Tacoma Community College Transit Center.  Capital cost for the 3.65 mile extension of light rail would range from $642m to $687m in 2014$.  Ridership would be between 6,000 and 8,000 passengers per day in 2040, adding to the projected 10,000 passengers per day from the Tacoma Link Expansion in 2035.

New Vehicles, Longer Platforms

Oddly enough, the extension to TCC has design considerations that would impact Final Design on the Tacoma Link Expansion currently programmed between Downtown Tacoma, the Stadium District, and Hilltop.  Passenger loads on the TCC extension cannot be met with Tacoma Link’s existing vehicles, even at 6 minute headways.  Sound Transit staff recommend replacing Tacoma Link’s fleet with 16 new light rail vehicles and retrofitting existing stations to be 98.5’ in length.  This would mean that all 7 stations in the Tacoma Link Expansion would need to meet the same standard to support getting to TCC. It would possibly save future costs if the five light rail vehicles not yet procured for the “Expansion” also met the new capacity standard.

That’s not all.

Upgrading Single Track

Puyallup Avenue couplet proposed
Tacoma Link Puyallup Avenue couplet proposed
(Source: TacomaTransit.  Artist: Anique Zimmer)

Single track along the Tacoma Link route south of S. 19th St at Pacific Avenue has been a limitation on vehicle headways ever since the City of Tacoma sponsored the creation of Commerce St. Station back in 2011.  Streetcar service in downtown went from every 10 minutes to every 12 minutes to ensure no conflicts on the section of bidirectional single track.  To support peak headways of service every 6 minutes and off peak service every 10 minutes, as Sound Transit believes necessary to provide ridership capacity, requires adding a northbound track from Tacoma Dome Station to Union Station via Puyallup Avenue.  This is a modification to the Tacoma Link system that has been long supported by TacomaTransit.  Provision of such track would allow the creation of two new stations along Puyallup Avenue.  Puyallup Avenue is also wide enough for the provision of exclusive rail transit right of way.

The level of “Ease of Non-motorized Access” for this particular corridor received a measurement rating of Medium-Low.  The document notes that there is a medium to low intersection density providing non-motorized access, with large parcels as barriers.  This alludes to pedestrian barriers to residential and commercial density, which support ridership.  The scale and lack of public access through Allenmore Golf Course, as well as the scale of Snake Lake Park, China Lake Park, and large block sizes in the vicinity of S. 19th and Union Avenue, all detract from walkability.  Only 25% of the land along the corridor is compatible zoned for transit oriented development.

As this project continues to develop, Sound Transit will have to evaluate other alternative corridors, such as 6th Avenue for ridership, costs, Ease of Non-motorized Access, and Transit Oriented Development potential.