[8] The Work Program was completed in April 2007 and concluded a two-mile (3.2 km) streetcar on Broadway and South Jackson Street would be a feasible way to connect First Hill with the light rail system while acting as a potential catalyst for new transit-oriented development.

[21] Other activists also petitioned the city for an extension to the business district on North Broadway, terminating near Aloha Street, which would require a separate funding source.

[25][26] The project also included the construction of a two-way protected bicycle lane on the east side of Broadway that was added as a result of cycling accidents on the South Lake Union line.

[32][33] Street construction and electrical installation were completed in late 2014, but the commencement of service was delayed to the following year due to procurement issues with the Czech streetcar manufacturer, Inekon Trams, and a Seattle-based partner that would assemble half the fleet.

[36] Passenger fares were waived entirely for the first two weeks of operation, leading up to a formal grand opening during a Lunar New Year festival in the International District on February 13, 2016.

[43] The First Hill line was criticized for its slow, meandering route without transit-only lanes or other priority measures to give it a time advantage over buses or pedestrians.

[48] SDOT planned to install a rubber flange filler between the track and concrete, but found that it would cause additional hazards and not last an adequate amount of time.

[51] Service resumed on March 20 after modifications to the load contactor were installed and tested; streetcars, however, remained temporarily restricted to 7 miles per hour (11 km/h) on the steepest sections of Broadway.

[52][53] SDOT announced plans in 2018 to improve streetcar service on Broadway by adding a southbound business-and-transit lane between Union and Madison streets and prohibiting certain turning movements at three intersections.

[2] A streetcar network plan published by the city government in 2008 explored extensions of the First Hill line to the Central District and on Rainier Avenue, connecting Broadway to the Mount Baker light rail station at Martin Luther King Jr.

[57][58] The 1⁄2-mile (0.8 km) streetcar extension was supported by community groups and merchants in the Broadway business district, who lobbied the city to study and design the $20 million project in 2010.

[62] Work on the project was halted in December 2016 and put on indefinite hold in October 2017 alongside street improvements, including the protected bicycle lane extension.

Mayor Jenny Durkan cancelled work on the project in March 2018 and ordered an independent review, which found that construction costs had risen to $200 million due to errors in vehicle procurement and design changes.

[70][73] The streetcar crosses a spur track on 8th Avenue South that leads to the line's operations and maintenance facility and then travels under Interstate 5 into Little Saigon.

[27] The streetcar stops in front of a community center and turns north onto Broadway,[70] which also carries a protected bicycle lane on its east side along with on-street parking spaces.

[27] The line then crosses into Capitol Hill and serves a set of stops between Pike and Pine streets in the center of the city's main nightlife district.

[75] Streetcars then pass the Seattle Central College campus and Cal Anderson Park before merging into a single track on the west side of Broadway.

[78] The platforms include a basic steel and glass shelter, a digital display with real-time arrivals, wayfinding maps and signs, benches, and leaning rails.

[88] The fleet was manufactured in Ostrava by Inekon and shipped to Seattle for final assembly by Pacifica Marine in 2015, falling significantly behind schedule and delaying the start of service.

[78] The streetcars are stored at an operations and maintenance facility within the city's Charles Street Service Center, connected via a spur track on 8th Avenue South.

The building was awarded LEED Gold certification for its sustainable construction, including a green roof and solar panels, and also houses administrative offices for the streetcar system.