WA: Light rail across Lake Washington: A preview before riders come aboard

One of Sound Transit's practice trips demonstrated the allure Wednesday of future light rail trains across Lake Washington.

The four-car train cruised at 55 mph over floating sections of the former Interstate 90 express lanes, with no shimmy and barely perceptible vibration.

The ride took only about five minutes, between the Mercer Island and Judkins Park stations. Window seats offered views of Mount Rainier to the south, Mount Baker to the north, and an expanse of glassy water in the foreground, a hint of smog and unseasonably blue skies.

Officials said they will announce the opening date Friday, for passengers to ride the 7-mile corridor that's now a gap between South Bellevue and International District/ Chinatown stations. The Eastside route, known as the 2 Line, will connect to the 1 Line in downtown Seattle and continue north to Lynnwood, while providing transfer connections to SeaTac and Federal Way. The full Eastside- Seattle line has taken nearly 18 years to deliver, plagued by planning and construction disputes.

Sound Transit CEO Dow Constantine, eager to reach the finish line this spring, declared before Wednesday's ride: It's coming up faster than you would have imagined."

Engineers spent years figuring out how to deal with lake levels that rise and fall 2 feet per year, along with junctions where floating pontoons meet the sloped transition spans, which hinge next to the fixed bridge segments over land. Instead of building slip joints or rails that move, they invented "a brilliant solution" where the steel rails remain continuous, but eight platforms flex under the track ties. These curved structures rest upon rows of wafer-shaped seismic dampers, like those supporting the roofs of T-Mobile Park and Lumen Field.

At full speed, the train passed one of these novel joint areas in silence, while another sounded like a rustling bag of toy marbles.

A couple times, the train slowed to 35 mph. Project Director Tony Raben said crews are fine-tuning the electric power flow between overhead wires and the railcars, but expect a continuous 55 mph when passenger service begins.

"It's going to be a very proud and moment for our region, finally uniting the west and east sides with high capacity transit," Constantine said, joined on the test run by Seattle Mayor Katie Wilson and Redmond Mayor Angela Birney, both transit board members.

Wilson said that as someone who doesn't own a car, "getting across to Mercer Island feels like a big deal … and so having the new Judkins Park station about to open up, and all of the connections between neighborhoods that's going to enable, it just feels really liberating."

Planning maps and ballot measures have tantalized commuters since the late 1960s with a train line drawn across Lake Washington. Voters in 2008 passed the ST2 sales tax increase to fund the project, along with recent extensions to Lynnwood, Bellevue to Redmond, and Federal Way.

The full corridor was supposed to open by 2020, but three years slipped because of route debates in Bellevue, and another three years when Sound Transit ordered contractors to rebuild thousands of track ties, known as plinths. Contractor Kiewit-Hoffman filed a formal claim in September for $184 million covering what it considered excessive changes and red tape, while Sound Transit sued in December, alleging defects in the original concrete and grout. The disputes remain unsettled, said Terri Mestas, deputy CEO for capital project delivery.

Sound Transit's board is scheduled to increase the budget $60 million Thursday, boosting the total to $3.82 billion between Seattle and Redmond Technology Station. The added money covers "additional startup costs, related to delays, including administration, quality control, security, and technical work, to prevent stray current from harming the bridge.

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