Commuters have waited years but finally, on Friday, the ribbon was cut on the Toronto-York Spadina Subway Extension.

Prime Minister Justin Trudeau and Premier Kathleen Wynne were among those on hand for the ribbon-cutting ceremony at Vaughan Metropolitan Centre — the first subway station outside Toronto’s borders.

“Today, we are proud to join with our provincial and municipal partners to celebrate the long-awaited opening of the new subway line — a line that will improve the quality of life of hard-working people and their families across the GTA.” Trudeau said.

Trudeau boarded the subway for its inaugural run from Vaughan Metropolitan Centre Station to York University Station.

However, riders will have to wait until Sunday morning to get the chance to experience the new six-stop line for the first time.

Wynne noted that this was the “biggest subway expansion in a a generation” and assured commuters that this would not be the end.

“This is a great day for commuters,” Wynne said. “Let me assure you that the 8.6 kilometres of new subway that’s being added to the system this weekend is a milestone — it’s not a finish line.”

The subway extension is two years late and over budget.

A CityNews exclusive investigation found that behind the scenes there is a battle being fought between the TTC and contractors who built the extension, which may mean the cost of the project will go up, again.

The extension was funded by all three levels of government.

“The subway extension is an example of the kinds of things we can accomplish when we work together to make a real difference in the lives of Canadians,” Trudeau said.

The ribbon cutting also marked the final project for outgoing TTC CEO Andy Byford.

Byford announced last month he would be leaving the TTC to take over as president and CEO of MTA New York City Transit.