TORONTO - Toronto Mayor Rob Ford is proposing private sector financing to fulfill his campaign promise to build subways instead of light rail.

Metrolinx, the Ontario-funded transit agency, says Toronto officials are proposing private funds could help pay for extending the Sheppard subway line.

Metrolinx president Bruce McCuaig says there is $8.15 billion available from the province for four light rail projects in Toronto.

McCuaig says Toronto approached Metrolinx on Tuesday with a proposal to go ahead with the Sheppard project as a subway rather than light rail.

McCuaig says Metrolinx is looking at the proposal and will be getting back to the city soon.

But he noted that any changes proposed by the city must deliver the same level of transit and stay within the budget.

Revisions must also "avoid the payment by the province of any penalties ... and minimize any delays in delivery of the project," McCuaig said.

McCuaig couldn't say how the latest Toronto proposal would affect contracts with Bombardier for nearly 400 streetcars and more than 200 subway cars.

Those contracts include a $770-million deal signed in June for Bombardier in Thunder Bay, Ont., to build an additional 182 streetcars for Metrolinx.

"It's too early to go into that level of detail," McCuaig said.

"One of the things we will be very interested in is the impact of any changes to the current plan that impact existing contracts," he said.

Ontario is covering almost all the capital costs for the four proposed light rail lines, while the federal government is funding one-third of the $950-million Sheppard LRT.

Transportation Minister Kathleen Wynne said the government wants to see the Toronto transit projects move ahead as quickly as possible.

"We're making record high investments because there's such a crying need for the congestion to be dealt with," Wynne said.

"There's some urgency to this," Wynne said. "This particular plan hasn't been analyzed but if it fits within the principles that we've been operating in then we want to get going."