[11] As passengers numbers were rising, the decision was made to upgrade parts of the bus system to rail transport.

On February 21, 2014, an 8-metre-wide (26 ft), 12-metre-deep (39 ft) sinkhole opened above the LRT tunnel excavation site at Waller Street south of Laurier Avenue, interrupting electricity, water, sanitation, and storm services in the area, and forced the rerouting of traffic and a temporary halt to LRT tunnelling.

The collapse forced evacuation of the Rideau Centre and the closing of a number of local streets and businesses; no one was injured or killed, but the nearly completed tunnel was flooded, submerging a roadheader.

[20] OC Transpo announced on August 23, 2019, that the testing had been completed by RTG and the Confederation Line would open to the public on September 14, 2019.

[21] On March 10, 2020, Ottawa City Council issued a notice of default to RTG, listing the flaws and problems with the line and its operation.

[22] On November 30, 2022, a public inquiry led by Justice William Hourigan issued a report criticizing both city politicians as well as the Rideau Transit Group consortium for problems in building and implementing the Confederation Line.

Hourigan found that project deadlines were unrealistic with unachievable dates, and that information about testing problems was disclosed neither to city council (other than to then-mayor Jim Watson) nor to the public.

[26] Station design concerns have been raised; shortcomings identified include steps that are slippery when wet, which have resulted in passenger injuries.

[27] The winning consortium for the project, RTG, awarded Alstom a contract to provide 34 Citadis Spirit LRVs.

Derived from the earlier Citadis Dualis tram-train used in Europe, they were manufactured in Alstom's plant in Hornell, New York, with final assembly taking place at Belfast Yard in Ottawa.

[32] Signalling on the line is handled by Thales' SelTrac semi-automatic communication-based train control (CBTC) technology.

[34] An additional 38 Citadis Spirit vehicles were ordered by the city as part of the Stage 2 extension project with assembly beginning in early 2019.

[38] Following the transition to full LRT service, in early October 2019 the automated doors of the Spirit vehicles experienced numerous faults if pried open or held back by passengers.

Because the original design of the vehicles did not include straps, RTG quoted the cost of procuring and installing them to be $1 million which OC Transpo rejected.

[45] RTG struggled to keep up with the maintenance of the vehicles leading to several weeks where only a reduced number of trains could be operated during peak periods.

On January 30, 2020, the Confederation Line reached an operational low when it was short five trains during rush hour due to "recurring mechanical and electrical issues".

[46] The Confederation Line was expected to field 15 working trains during rush hour, although it only operated 13 vehicles at once during peak periods due to the system requiring more spares than originally thought.

The changes were meant to provide extra service to those in areas affected by the Transitway closure, and to avoid as many delays as possible while construction on the Confederation Line progressed.

[67] Stage 2 will add a new light maintenance and storage facility along Corkstown Road, west of Moodie station, Line 3's western terminus.