were any of them approved?
Yes, a proposal as part of the Forward Thrust initiatives was approved.
Downtown Seattle Transit Tunnel
The most significant rapid transit proposal came as part of the Forward Thrust initiatives of the late 1960s, which was centered around a downtown subway under 3rd Avenue. The subway would be fed by lines from Ballard, Lake City, the University District, Capitol Hill, Bellevue, and Renton, combining for a planned minimum headway of minutes at rush hour, minutes during midday, and five minutes at all other times. The stations on 3rd Avenue were to be situated at South Jackson Street and 5th Avenue South, James and Cherry streets, Seneca and Spring streets, and Pike and Pine streets, all planned to open by 1985 and operated by the Municipality of Metropolitan Seattle. Seattle voters were asked to provide $385 million (equivalent to $ in dollars), to supplement a $765 million grant (equivalent to $ in dollars) from the Urban Mass Transportation Administration (UMTA), during a municipal election on February 13, 1968, narrowly passing the bond by 50.8%, but falling short of the required 60 
where is downtown seattle transit tunnel? Seattle, Washington, United States who built it? UNANSWERABLE which are the different stations that the tunnel connects to? Westlake and International District/Chinatown stations does it also connect to any route? Yes, it connect bus routes. how does the transit run? The OCC controls vehicle movements by using on-board radio-frequency identification tags installed on tunnel buses and light rail vehicles, their locations tracked by passing over induction loops embedded in the tunnel roadway. were there any proposals made to make a subway ealier? Yes, there were several proposals for a cut-and-cover subway tunnel.
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Downtown Seattle Transit Tunnel [SEP] Previous subway proposals
Several proposals for a cut-and-cover subway tunnel under 3rd Avenue in Downtown Seattle were presented to the City of Seattle by predecessors of the Seattle Planning Commission throughout the 20th century. The first major proposal was part of urban planner Virgil Bogue's "Plan for Seattle" in 1911, as Route 1 of a proposed rapid transit network. Route 1 ran southeast on 3rd Avenue from a circular ring around a proposed civic center in the Denny Regrade neighborhood to King Street Station, paralleled to the west by a subway on 1st Avenue known as Route 17; stations on the line were to have additional entrances from department stores and other major businesses on 3rd Avenue.