Traditionally, government infrastructure projects are financed and managed by the government, and private corporations are contracted to build and maintain the project.
In a public-private partnership (P3), the government commissions a private partner who is responsible for the entire project. The private partner is responsible for Design, Building, Financing, Operating, and Maintaining the project for some amount of time (DBFOM). As a result, the private partner retains revenue from the project (e.g. Vancouver SkyTrain’s Canada Line).
The federal government of Canada recently announced high-speed rail connecting the Toronto–Quebec city corridor. This project is a traditional contract project.