Contractors are building a replacement Metro Transit traction power substation – a mini powerhouse – near the mouth of the Downtown Seattle Transit Tunnel. This will allow an existing traction power substation located on Metro’s Convention Place Station property to be removed.
The traction power substation is a mini powerhouse that powers a quadrant of trolley wires used by routes 10, 43, 47, 49, and 70 serving all electric routes on Union, Pike and Pine between First and Seventh avenues. Metro built it on transit property tucked under a ramp that connects CPS with Olive Way. The mini powerhouse is about 15 feet by 45 feet.
As King County prepares to sell Convention Place Station for redevelopment, regardless of the developer, Metro needs to move this infrastructure.
Metro estimates it will cost $9.7 million to $10.2 million to purchase and install a new traction power substation and remove the old one. Contractor crews began bringing in equipment and materials to Convention Place Station April 3, with work focused from 1 a.m. to 4 a.m. on weekdays. On April 22 and 23, crews created a safe work zone by demolishing some curbing to allow buses to maneuver around the work area. With this work completed, work will commence in the tunnel portal approximately May 2. Buses will still be able to travel in and out of the DSTT, but flaggers will be present to guide bus drivers through the work area during nighttime work hours,when bus service is lighter. Crews plan to build a new foundation near the tunnel portal underneath Ninth Avenue and install the new traction power substation to power Metro Transit trolley buses. The system will be connected to the power grid and the old substation will then be removed.
Transit riders can expect to experience only minimal delays or inconveniences. Flaggers will be present to guide buses through the construction area, which may result in brief delays. After 9 p.m. on weekdays, riders of the Routes 101, 150, and 550 will need to use Bay I for boarding and deboarding, instead of Bays C, D, and E. Riders of the Routes 41 and 255 will continue to use Bay A for boarding and Bay I for deboarding, as they do today. Riders of the Routes 74 and 102 will not be affected, as these routes do not operate after 9 p.m. Metro worked with contractors to ensure that transit access to the tunnel is maintained at all times during construction except during a handful of upcoming weekend closures. Riders will follow signs to available stairs, escalators and elevators to safely access the available transit bays at Convention Place Station. Transit security will monitor construction site access and Metro Transit Police will monitor Downtown Seattle Transit Tunnel access during construction. On certain weekends yet to be determined, contractor crews will do work that requires Metro to temporarily completely close Convention Place Station and reroute buses to surface streets, following service patterns established for times the DSTT is otherwise closed due to an incident.
Crews will relocate other critical infrastructure as the site is prepared for sale, including life safety and tunnel control systems. Further steps to create an interim access ramp from Convention Place Station to Ninth Avenue is scheduled to begin this fall, which will affect where riders board transit. Under a pending purchase and sale agreement for the sale of Convention Place Station, Metro Transit will cease joint operations in the DSTT and route bus service out of the tunnel and onto surface streets as soon as September 2018.