The federal government will kick in $1.3 billion towards an extension of the Montreal metro system's blue line.

Prime Minister Justin Trudeau was joined by Mayor Valerie Plante, Quebec Junior Transport Minister and Minister Responsible for Montreal Chantal Rouleau and Minister of Canadian Heritage Pablo Rodriguez for the announcement in St-Michel on Thursday.

"There has been consisted under-investment in public transit in Montreal and, indeed, across the country over the past years," said Trudeau. "That's why we're so pleased that we're moving forward today on a $1.3 billion investment into making the blue line extension a reality."

The extension of the blue line has been expected for several years and has been repeatedly announced by successive governments – in fact the project was first announced by PQ premier Rene Levesque in 1979. Generations later, the Parti Quebecois pledged to build it a few months before they were defeated in the 2014 election. Construction was to have been completed in 2020. In April 2018, Trudeau announced alongside Plante and then-premier Philippe Couillard that the extension serving the northeastern part of the city should be completed by 2026.

The 5.8-kilometre project involves five new stations linking the Saint-Michel station to the Anjou station in East Montreal. According to previous reports, the new stops will roughly line up with Jean-Talon Blvd., with stations located on Pie-IX, Viau, Langelier, Lacordaire, and Anjou.

The blue line extension is expected to provide metro access to more than 17,000 new users, and will include two new bus terminals and park-and-ride lots in the area.

The City of Montreal's estimates predict that the project will cost about $3.9 billion though that number has been disputed by critics who say it will likely cost closer to $4.5 billion.

The provincial government has so far not said how much of the bill it is willing to foot.

"We know the last government said it would cost $3.9 billion and not long ago we saw it was closer to $4.5 billion," Rouleau said to reporters after the announcement. "What I'm saying is we are refining the costs."

Part of that refining process will be to settle with property owners along the metro's proposed route who aren't happy with the government's offer. "It's a negotiation between the property value and the market value," Rouleau said to a question about how much the province offers owners to expropriate their property.

"I can't go into detail because it's in litigation," she said.

Last year, Quebec City and Ottawa each contributed $16 million for the creation of a project office. The Couillard government paid an additional $330 million to start the process of acquisition and expropriation.

Construction on the new section of the metro line is expected to start in 2021 with an opening date in 2026.

In a statement, the STM said residents in the area will see teams in the field this summer as they conduct surveys and geotechnical tests between St-Michel metro station and Highway 25 in Anjou. According to the STM, the "work has been planned to keep impacts to a minimum."

"Priorities identified include ensuring the urban integration of the project and the stations’ architectural design, coordinating work taking place on public property, and implementing effective mitigation measures during these processes," they said.

East End merchants welcome extension

Residents and businesses in Montreal's East End welcomed the announcement, saying they hope the extension will breathe new life into neighbourhoods near the new stations.

Paul Micheletti, president of the Jean-Talon West Society for Commercial Development, said the extension would be an economic boost but said there are concerns. He said that since most of the stations lie along Jean-Talon, there would likely be much roadwork and sewer work in the short term that could affect businesses.

He said he's planning to assemble a committee with the city and STM to ensure businesses aren't harmed by the construction.

"We need to plan the transition from 2020 to 2026," he said. "We don't want to have the mess we've seen on some of the streets where it becomes a ghost town as merchants close and business becomes impossible. We're really working on the transition. We've been planning for this for almost 18 months already."

Some businesses have already received expropriation notices. In their statement, the STM said the impact on residents and businesses are being taken into account when decisions are made about expropriation.

"At this stage, the expropriation process is already underway for 20 lots from 17 owners," they said. "Information meetings with tenants are set to take place this fall to help them better understand the process and their options. The procedures for the acquisition of public property and easements on public property are also well underway."

- With files from Giuseppe Valiante of The Canadian Press