Despite the sharp drop in air travel during 1989-91 thanks to the post-oil crisis recession and elevated price of jet fuel hammering Boeing, Seattle's burgeoning trans-Pacific trade, life sciences and software industries had helped buoy it through the worst of the early 1990s economic crisis. As such, it earned a reputation as "the city on the move," and the ambitious young Mayor, Norm Rice, came to office in June of 1988 with a goal of dramatically expanding the city's transportation infrastructure in addition to its hotel, housing, and office capacity. By the early 1990s, however, the Seattle Subway was fairly established within city limits and the split government in Olympia was adamant that further transportation improvements help residents outside of the city core, which had been part of the reason Lines 7, 8 and 9 had extended to places like Seattle-Jackson Airport, Tukwila, and Burien. The next block of lines were intended to route eastwards, across Lake Washington.
Governor Tim Hill, a progressive Liberal, partnered with Rice and, starting in January 1993, President Robert Redford's Department of Transportation to route huge amounts of money to Washington state in order to expand passenger rail, highways and bus service, and key to that plan was improving connections of the Subway across the lake at the same time that the Soundrail S-train service around the north and south sides of the lake were built out for less-frequent service on mainline rail. These decisions were made possible only by the USOC declaring in December of 1992 that Seattle was its preferred candidate city over Salt Lake City for the 2000 Winter Olympics, which gave the "Olympic Lines" a major boost, especially as it seemed highly likely that the IOC would pick Seattle at its September 1993 meeting. When the Olympics were indeed awarded to the Puget Sound region, the massive expansion of the transport network was deemed a major reason why. With four lines being opened, though two of them almost entirely using existing right-of-way, it was the largest expansion of the network since the original Bogue Plan in the 1930s.
Line 10 - Alki to Redmond
Engineering constraints essentially dictated that any line across the Lake Washington Floating Bridge would have to follow the course of Interstate 90 across Mercer Island, the Rainier Valley Viaduct, through the Beacon Hill Tunnel and onto either the Spokane Street Viaduct or the Eighth Avenue Elevated. Planners eventually elected to go with both, giving the booming city of Bellevue across the lake two lines through its downtown, and the first of these lines would be Line 10, which would fully open after a twelve-month delay in November of 1999 - barely in time for the Olympics - and become emblematic of the boondoggles associated with the rushed Olympic Lines. Construction problems plagued Line 10 from the get go; there were issues with engineering the tracks on the floating bridge, litigation around the route of the line near the sensitive Mercer Slough bogged down construction in Bellevue, and soil problems in drilling towards Alki in West Seattle pushed back construction months as the project was re-engineered. It was only the disastrous events in Chinatown on the main feature of the Olympic Line project, which Line 10 was unaffected by, that allowed it to open first.
Line 10 begins at a large station with shopping and community amenities a few blocks off of Alki Beach in West Seattle and proceeds into a tunnel with a stop under the Admiral neighborhood, then exiting that tunnel and joining Line 9 on a wye onto the Spokane Street Viaduct, with a massive, four-story new infill station built in 1998 at Spokane Street to allow connections to trains running towards Seattle-Jackson Airport such as Lines 7, 11, and 13. From there, rather than exit onto the Eighth Avenue Elevated towards the Dearborn Trunk, the train goes into the Beacon Hill Tunnel, with a stop under Beacon Hill, before proceeding out onto the Rainier Valley Viaduct, where another massive new station was built in the median and under the overpass to provide a connection to Line 3. The train then proceeds across the Lake Washington Floating Bridge, with a stop at the south end of the town of Mercer near the entrance to Mercer Island State Park.
After Mercer Island, the line remains elevated through the Mercer Slough, with a stop at Slough Station, and then enters another tunnel with a stop at West Bellevue before entering the city's downtown at Main and Bellevue Way, where it has one deep-bore station and continues to a second stop under Bellevue Way with entrances at 4th and 6th, placing it directly in front of Bellevue Center shopping mall and across the street from, at the time of its opening, additional major shopping, office and residential developments. The line then curves north to stop at 110th Avenue and 8th Street, passes under Interstate 5, and initially came to a stop at Bellevue Intermodal Station, where it aligned with the Soundrail S-train service.
Due to this stop's proximity to major tech firm Windows' campus just a few blocks away, in 2004 an extension was approved all the way to Redmond, which was opened in phases in 2009 and 2013, with the line emerging from a tunnel near its operations and maintenance center to run on an elevated guideway through the technology campuses of the Northup Area and then through the Overlake neighborhood all the way to downtown Redmond, where it stopped half a block from Redmond's own Soundrail station. The construction of this line is widely credited with the apartment and office boom on the Eastside during the 2000s and early 2010s despite the Seattle region's broader economic struggles thanks to the tech bust and Asian financial crisis of 2002.
