The most prominent was the Seattle Monorail Project, founded by a 1997 ballot initiative to build a citywide network that would expand coverage beyond the planned Link light rail system.

[8][9] The monorail tracks cross over Broad Street and travel along the west side of 5th Avenue North for two blocks, passing the KOMO Plaza news broadcasting center.

[13] The monorail passes by several city landmarks, including the Amazon Spheres and Westin Seattle towers, eventually reaching McGraw Square, where 5th Avenue makes a slight turn to the south.

[55] The Seattle city government, supported by civic boosters and the state legislature, began planning for its second World's Fair in 1955 to celebrate the 50th anniversary of the 1909 Alaska–Yukon–Pacific Exposition.

[68] In April 1959, the Seattle Transit Commission chose Lockheed to build the $5 million monorail system, which would travel along 5th Avenue from Pine Street to the fairgrounds and open in 1961.

[71][72] The operating costs were expected to be paid through fare recovery, while other options were considered for capital funding, including Lockheed buying back the system after the world's fair.

[73][74] Lockheed entered into final negotiations with the city and exposition organizers in late 1959, but the transit commission lost interest in running the system after the world's fair was shortened to six months instead of the original eighteen.

[75] The system's uncertain financing, not including engineering costs incurred by Lockheed, remained a major concern for the city government as negotiations continued into January 1960.

[88] Century 21 announced plans in April 1961 to build a small-scale people mover around the fairgrounds that would use a suspended monorail, but they were dropped five months later after the bidding firms were unable to obtain financing.

[92][93] The construction permit included a requirement to remove the monorail within six months of the exposition's end, but Alwac had announced their intention to sell the Alweg system to the city government if they desired.

[103] The monorail's 60-short-ton (54,000 kg) precast concrete beams were assembled in Tacoma and trucked up to Seattle, with special permission from the Washington State Highway Commission,[104] and the first was installed on September 21 between Virginia and Stewart streets before advancing northwards.

[121] Several test runs were made into special occasions, including a trip that was televised live by KING-TV and a preview ride for 175 dignitaries after a ribbon cutting at the Westlake terminal on March 12.

[127] The inaugural monorail trip from the Westlake terminal carried 130 passengers who received commemorative medals, including the first riders, who had lined up several hours early.

[149][150] Seattle Center reopened for the summer season on June 1, 1965, with monorail fares lowered the following day to 25 cents for adults on a one-way trip to attract more patrons.

[159][160] The plaza at Westlake Mall was sought as the location of an expanded downtown park, leading to a major renovation of the monorail terminal that began in January 1968 and completed in April 1968.

[161][162] Reduced monorail service continued while the terminal was shrunk with the removal of the outer platforms deemed unnecessary for post-fair demand and the replacement of the roof with a simpler design.

[167][168] The city considered several proposals for a shopping mall on the block on the north side of Pine Street in the 1970s, including hotels, movie theaters, a potential home for the Seattle Art Museum, and a new monorail terminal, but they were never realized.

[191] The discovery was made when a retractable boarding ramp at the terminal scratched the blue train during a test run; a hinge pin that failed to fold properly was identified as the cause for the misalignment.

[200] In July, the city council passed the landmark ordinance to provide protections to the two Alweg trains, but excluded the guideway to support its reuse for the expansion project.

[205] On June 29, 2023, a set of 16 monorail columns on 5th Avenue between Olive Way and Vine Street were painted with portraits of Major League Baseball (MLB) players and local sports fans.

In 1961, businessman Ben B. Ehrlichman proposed that the then-unfinished monorail be extended north to Alderwood Manor or Mountlake Terrace and south towards Seattle–Tacoma International Airport, Kent, and Renton.

[214] The Forward Thrust program included a ballot measure that would build a conventional rapid transit system serving King County with federal funding, but voters rejected it in 1968 and 1970.

Taxi driver Dick Falkenbury conceived a separate proposal in 1996 to build a citywide monorail system and submitted a ballot initiative after a signature-gathering campaign.

[63][225][226] 53 percent of voters approved the monorail plan, named Initiative 41, in a general election on November 4, 1997, creating the Elevated Transportation Company (ETC) to seek financing.

The tax was adopted through a ballot measure that voters narrowly approved in the November 2002 election, creating the Seattle Popular Monorail Authority to manage the program.

[231] The project was stymied by tax revenue that was lower than expected and design changes to keep construction costs within the proposed budget and open by 2009—a two-year delay from the original plan.

[234] A revised cost estimate of $11 billion, including debt payments until 2050, was unveiled later that month and withdrawn by the Seattle Monorail Project after public criticism from elected officials.

[238] The "Green Line" corridor from West Seattle to Ballard was later included as a light rail project in the Sound Transit 3 ballot measure, which was passed by voters in 2016.

[242] The first major accident involving the monorail occurred on July 25, 1971, when a brake failure on the red train caused it to strike a girder at the end of the track in the Seattle Center terminal.

[244][245] The red train was lifted off the track and moved to a Seattle Transit System maintenance facility in August for a complete rebuild of the front car at a cost of $100,000 (equivalent to $576,000 in 2023 dollars).