Tom Mulcair said he will "make sure" the Scarborough subway will move forward if he is elected prime minister in the fall.
"We will make sure that that project continues through," the NDP leader said at a news conference in Toronto on Friday.
Mulcair said his government would respect the $660 million in funding that was promised by Conservative Leader Stephen Harper in 2013.
"We want to become the reliable, long term partner of municipalities and regional governments across Canada. We've put very specific undertakings in our budget proposals to do just that, but we're not going to start talking about reversing decisions that have already been taken."
The Liberals have also vowed to provide transit funding to local governments, saying they will leave specific details of transit lines up to local city councils.
The issue of the Scarborough subway was brought up because of the nomination of a new NDP candidate. Olivia Chow was officially nominated as the NDP candidate in the riding of Spadina-Fort York on Thursday.
Chow is the former representative of the riding, but resigned from the position so she could run for mayor of Toronto in 2014. During her mayoral campaign, Chow vowed she would put an end to the controversial subway expansion in the city's eastern borough. (http://toronto.ctvnews.ca/where-the-top-mayoral-candidates-stand-on-key-issues-1.2034386)
Speaking to reporters on Thursday, Toronto Mayor John Tory said his objective through the federal election campaign would be to get all party leaders and candidates on board with transit projects like the Scarborough subway.
"The people of Toronto will know, regardless of how they cast their vote, those transit projects will be funded by that level of government," Tory said.
The subway project was first announced in July 2013, when members of Toronto City Council voted to extend the Bloor-Danforth line into Scarborough rather than to move ahead with a previous plan to build a seven-stop light-rail like to replace the aging Scarborough RT. Two years after the subway plan was approved, officials are still working to narrow down the specific details of the project.
