Sound Transit begins building light rail on interstate bridge

Sound Transit has begun building light rail in the center lanes of the Homer M. Hadley floating bridge across Lake Washington. The work on Interstate 90 is part of the agency's 14-mile East Link light-rail extension project.

Constructing light rail across a floating bridge marks a world-first achievement, Sound Transit officials said in a press release. The track on the bridge was engineered to compensate for six ranges of lake motion, according to the agency.

Construction on the bridge will continue through 2020. The work includes installation of an overhead catenary system, electrical and control systems, signals, cathodic protection, and traction power substations.

"In just a few years, Eastside light-rail riders will be able to cross the floating bridge safely and reliably in about a minute, no matter how congested traffic gets on [Interstate 90]," said Sound Transit Chief Executive Officer Peter Rogoff. "This project, in the making for four decades, moves the region forward in building a critically needed transit connection between Seattle and the Eastside."

The new bridge is being built despite earlier skirmishes with the city of Mercer Island, Washington. The city in February pursued legal options against Sound Transit and the Washington State Department of Transportation to halt the project due to concerns about impacts on vehicular traffic.

However, the city and Sound Transit settled the issue in early June, The Seattle Times reported.

The East Link extension will run from downtown Seattle to downtown Bellevue, Washington. The line also will serve the Overlake area of Redmond, Washington, via I-90.

All segments of the East Link project are under construction, with the entire line slated to be operational in 2023.