After revising the opening date of the central section to 2023 and then, amid ongoing legal action against Crosslinx (the construction consortium), Metrolinx stated they believed there was no credible schedule to complete the project.

On February 8, 2012, in a special meeting, Toronto City Council, led by Karen Stintz, voted 25–18 to override Mayor Ford's modifications to the project.

In 2012, Metrolinx discovered that there would be minimal cost differential between tunnelling under the West Don River at Leslie Street (the proposed location of the Sunnybrook Park stop) versus laying the track on the surface.

[37][40] Members of the public asked Metrolinx why it was proposing a centre-of-road alignment instead of running the tracks on the south side of Eglinton Avenue through the valley at Leslie Street.

They also stated, "It is very difficult (if not impossible) to relocate the portal from the centre of Eglinton (as proposed in the current design) and shift it to the south side of the right-of-way and continue to use the existing bridge.

However, during his successful campaign in the 2014 Toronto mayoral election, John Tory proposed SmartTrack, which would have included a heavy rail transit line established along this section of Eglinton Avenue.

[49][50] The 2010 Environmental Assessment for Transit City originally considered an entirely at-grade light rail line running west from Weston Road and Mount Dennis station.

[58] The decision to run trains above ground near the proposed station at Jane Street led to protests from late 2022 and the erection of a tipi and other temporary structures by local First Nations groups from early February 2023.

[62] During the 2018 Ontario general election, Liberal and Progressive Conservative candidates for Etobicoke Centre, Yvan Baker and Kinga Surma respectively, supported the underground option.

[64] Crosslinx Transit Solutions (CTS), a consortium of more than 26 companies, was awarded the contract to design, build and finance the Eglinton Crosstown line and to maintain it for 30 years.

[9] In July 2015, the Crosslinx Transit Solutions Maintenance General Partnership consortium awarded Bombardier Transportation a 30-year contract to maintain Line 5's light-rail vehicles.

[76] The TTC also warned that Metrolinx's aggressive timeline would lead to severe construction-related disruptions to communities and traffic because large stretches of the Eglinton Avenue would have to be torn up concurrently to meet deadlines.

[80] On November 12, 2013, Metrolinx awarded a contract to a joint venture between Aecon Group and ACS Dragados Canada to construct the tunnel for the eastern portion of the line between Yonge Street and Laird Drive.

[81] 2014 In March 2014, work began to clear utilities and trees on the south side of Eglinton Avenue just east of Brentcliffe Road to set up the eastern launch shaft.

[83] For the year prior to May 2014, the two TBMs Dennis and Lea had been excavating and installing concrete tunnel liners at a rate of approximately 10 metres (33 ft) per day.

[87] By September 2015, the TBMs Don and Humber arrived for assembly in the shaft at Brentcliffe Road before starting to drill the 3.25-kilometre (2.02 mi) section west to Yonge Street.

[89] On November 3, 2015, Del Duca announced that the contract awarded to Crosslinx Transit Solutions to complete the Crosstown and maintain it for 30 years will cost $2 billion less than originally estimated.

[72] On April 18, 2016, at the site of the future Forest Hill station, the façade of the former House of Chan restaurant and the scaffolding that was holding it up collapsed, injuring seven people.

[111] In November 2019, Crosslinx informed Metrolinx that it expected the line not to be completed before May 6, 2022, and that the construction costs would total $12.58 billion, an increase of $330 million over previous estimates.

On December 17, Crosslinx conducted an inaugural run with staff and guests from the handover platform at the EMSF to the elevated guideway over Black Creek Drive.

[117] In early March 2020, the provincial government announced it would provide $3 million in aid to local merchants negatively affected by Crosstown construction near their businesses.

[119] On March 9, 2020, Crosslinx began work to extract tunnel boring machines Dennis and Lea at Duplex Avenue, one block west of Yonge Street.

[139] In March 2022, Metrolinx announced that all 76 of the light rail vehicles had been brought together at the Eglinton Maintenance and Storage Facility, the fleet's final deliveries having arrived in 2021.

[19] On September 27, 2023, Metrolinx CEO Phil Verster announced he would not give an estimated opening date for Line 5 until after "high-risk testing and commissioning work is completed".

[147] 2024 On March 25, 2024, Metrolinx CEO Phil Verster stated that all major construction had been completed but that the most serious obstacle remaining was defects in software for the signalling and train control system.

On March 10, 2020, Metrolinx and Infrastructure Ontario issued a request for qualifications (RFQ) for the construction of tunnels, marking the first phase of procurement of the western Eglinton extension.

[154] On December 2, 2021, Metrolinx and Infrastructure Ontario issued the request for qualification (RFQ) for the construction of tunnels between Jane Street and Mount Dennis station.

[159][160] The initial business case indicates intermediate stations at Convair and Silver Dart, with the terminus at Pearson Airport's planned Regional Transit Hub.

Green track will dampen train sounds, absorb runoff water, reduce ambient temperatures in summer and minimize the spread of dust.

Because of the controversy surrounding the artwork LightSpell at Line 1's Pioneer Village station, in which commuters could have displayed inappropriate messages that violate TTC By-Law No.