The Ontario government is pitching it as a bargain.

Transportation Minister Steven Del Duca says the 30-year, $9.1 billion contract to build and maintain the Eglinton Crosstown LRT is actually about $2 billion below estimates.

He credited the province's public-private partnership system, administered by its agency Infrastructure Ontario, for inking a deal below the forecast $11 billion.

The contract with Crosslinx Transit Solutions, a giant consortium, was announced last summer. But the cost of the contract was only revealed on Tuesday at a downtown P3 conference.

The agreement covers all aspects of the transit line except the tunneling, which is already well underway. The TTC is expected to operate the LRT.

"Because we were able to leverage (Crosslinx's) creativity and their innovation, the dollar figure has come back in at $2 billion lower than originally estimated," Del Duca told reporters.

He said he didn't know the value of the only other bid.

Of the $9.1 billion, $5.3 billion is capital. The remainder goes to financing, lifecycle and maintenance costs.

Crosslinx is comprised of SNC-Lavalin, Aecon, EllisDon, Stantec, ACS Infrastructure Canada, Dragrados and IBI Group. It will build 15 underground stations on the central section of the 19-kilometre LRT at a cost of about $80 million to $100 million each. It will also build 10 street-level stops for about $3 million to $5 million each.

"The P3 or alternative financing and procurement (AFP) delivery model protects taxpayers by transferring significant risks to the private sector and provides the opportunity for innovation in design and construction," Del Duca told the conference.

The Crosstown will run about 19 kilometres from Mount Dennis in the west to Kennedy Station in the east. The central section will run underground.

Of 45 Infrastructure Ontario projects substantially complete by March, Del Duca said 44 have come in on budget.

But P3 opponents say that the public projects built with private sector money inevitably cost taxpayers in the longer term.