May 12, 2017
By: Mike Lindblom
(The Seattle Times) Sound Transit will soon try something unprecedented — building and operating train tracks on a floating bridge. The work begins June 3 in the center express lanes of Interstate 90, after carpools, buses and Mercer Island motorists are kicked out to make room for light-rail contractors. Passenger service between Seattle, Bellevue and Overlake is scheduled to begin in 2023. The technical challenges are daunting.
Engineers have to ensure the bridge will remain buoyant when a pair of 300-ton trains pass each other, and that the high-voltage current that powers the trains won't stray into the bridge's pontoons and corrode its steel rebar. They spent $53 million just to design the section across Lake Washington. The most difficult task is adapting the rails to the movements of the bridge...
Read More At The Seattle Times: http://www.seattletimes.com/seattle-news/transportation/light-rail-track-floating-bridge-i-90-sound-transit/