Increased use of streetcars is a large part of Toronto's Transit City plan. (Carolyn Ryan/CBC)

Plans drawn up by Metrolinx, the new provincial agency co-ordinating transportation issues across the GTA, are threatening to derail Toronto's Transit City light-rail plan.

Metrolinx is presenting its plan to its board at a retreat this weekend. But leaked copies of the plan suggest it will meet with resistance from Toronto politicians.

Mayor David Miller, a member of the board of Metrolinx, is on record as a strong supporter of the Transit City plan.

"It meets the city's needs for at least the next 30 years ... it works and it's affordable," he said recently.

But Toronto's plan is at odds with the blueprint drawn up by Metrolinx.

Transit advocate Steve Munro has seen a version of the Metrolinx confidential draft plan, and says that instead of streetcars, Metrolinx wants a subway-like rapid transit line along Eglinton Avenue, from Scarborough to Pearson International Airport.

At $6 billion, the plan will cost three times what the city had budgeted.

"If you build a much more expensive Eglinton corridor, [then] that's money that won't be available to build projects elsewhere," said Munro.

But Rob MacIsaac, chair of Metrolinx, said local priorities will be part of the grand plan. Toronto and other municipalities, he said, should be prepared to compromise.

"The heart and soul of Transit City will be respected by the regional plan we're proposing," said MacIsaac.

But Munro says any battle between Metrolinx and Toronto will only hurt the people it is ultimately trying to serve — public transit users.

"The first and major concern that I have is that the importance of local transit has just about completely fallen off of the plan. Without good, strong local transit services feeding into whatever network was built, Metrolinx, you know, you really don't have a network," said Munro.