Proposals for a modern streetcar or light rail along the Hiawatha Avenue corridor appeared in the pages of the Star Tribune as early as 1974.

Rail projects struggled to gain political support until the 1990s, when several factors combined to make the idea more palatable.

Governor Tim Pawlenty had campaigned on a promise to fight the expansion of light rail, but altered his opinions after taking office.

In addition to the available land, the desire to connect to the airport and at least reach the vicinity of the Mall of America proved to be the bigger draw for decision-makers.

[11] The idea of running a rail line down Hiawatha Avenue had already been around for at least a decade by the time the decision was made to go forward.

In 1985, the Minnesota Department of Transportation (Mn/DOT) had produced an Environmental Impact Statement that concluded that light rail was the best alternative for the corridor.

[12] In 1996, the document was examined again as Mn/DOT looked at the possibility of adding bus rapid transit along the road, but money for light rail became available soon after, leading to the current layout.

Initial designs cut out the last stop in downtown, and the southern end of the line did not quite connect to the Mall of America.

It was completed later than what was initially hoped for (a lot of literature points to 2003 as the opening year), but the mall connection was a significant contribution to the extra time requirements.

Certain aspects of the design had been tried before, but the cars were the first to combine the factors of conforming to American standards (as opposed to European), having low floors and being built at the company's Mexico plant.

Testing of the track and vehicles continued during the bus strike, as much of the work was performed by Bombardier employees rather than Metro Transit workers.

According to Metro Transit, the project consists of replacing sections of tracks that "have worn out and upgrades technology that guides safety systems."

Ryan Heath, engineer for Metro Transit who is overseeing the project, said that "this is important for the Blue Line's next 40 years.

[22] The Blue Line runs from downtown Minneapolis to the Mall of America for a length of 12 mi (19.3 km).

[23] The station offers connections to the Red Line and other local bus routes including those operated by Minnesota Valley Transit Authority.

The route travels through Bloomington's South Loop District before reaching the Terminal 2–Humphrey station of the MSP Airport across from Fort Snelling National Cemetery.

Trains travel on bridges over traffic at busy intersections near Lake Street and Franklin Ave with overhead stations located at each crossing.

After crossing I-35W on a dedicated bridge, the train begins to share tracks with the Green Line and enters downtown by traveling around U.S. Bank Stadium.

Due to the unique makeup of Minneapolis' population, ticket-dispensing machines present instructions in four languages: English, Spanish, Somali and Hmong.

The extensions were paid for primarily with federal money but the Metropolitan Council, Hennepin County, and city of Bloomington also contributed some funds.

Fares are purchased before boarding, either at ticket machines located in the stations or by scanning a Go-To card at dedicated pedestals.

This is the same height as the rail platforms, allowing stepless access for passengers dependent on wheelchairs or other mobility aids.

Each vehicle has a number of cameras on board, pointing both inward and outward, to monitor passenger activity and other areas of interest for security and safety.

Video feeds and the position of each vehicle on the line are monitored in a control room at the system's maintenance facility, located between Cedar-Riverside and Franklin Avenue stations.

According to Metropolitan Council meeting notes dated July 30, 2010, for the August 9 Transportation Committee meeting, Siemens Industry Incorporated agreed to build the Light Rail Vehicles for the three-car train expansion project in a joint procurement with the Green Line's initial LRV procurement, at a per-LRV cost of $3,297,714 and a total contract value of $153,211,516.

[42][43] After two more people were killed in separate incidents on the Blue Line, one a bicyclist and one a man in a wheelchair, signs saying "See Tracks?

[46] Additionally, there has been concern over violent assaults, robberies, and disorderly conduct that occurs on the station platforms while people wait for the trains.

[47] Aggravated assaults, which involve the use of a weapon to cause serious injury, continued to increase through 2019 including another murder by stabbing at the Lake Street/Midtown station in October 2017.

[49] In January 2020, the Met Council approved $1.3 million in spending to install new 360-degree 4K resolution cameras on all Metro Transit light rail cars by the end of 2020.

[50] Another stabbing that resulted in death occurred on a train in Bloomington in January 2020, but no charges were filed due to claims of self-defense.