Historically, the city would have raised the money to build the system, then hired companies to design and build it. Whatever emerged would be maintained by city.

But the design, building and construction and construction financing of Ottawa’s system was turned over to a specially created company owned by ACS Infrastructure, a Spanish engineering company; Ellis-Don, a construction company based in Mississauga, Ontario; and SNC-Lavalin, the Montreal-based engineering company that was the talk of Ottawa for other reasons this time last year. Those three companies also received a second contract from the city to maintain the system for the next 30 years.

Matti Siemiatycki, the director of the School of Cities at the University of Toronto who has long studied 3Ps, told me that Ottawa’s mess was being widely followed.

“It really starts to raise questions about whether public-private partnerships are a model that’s going to persist, to continue to deliver these big projects,” he said.

Projects built through this system, Professor Siemiatycki told me, generally cost more. But the theory is that if private sector companies effectively “own” projects, they will be driven to build them on time and on budget and ensure that they work properly.

The process has been used throughout Ontario and in other provinces, particularly British Columbia, to build hospitals, courthouses and schools, and the federal government under Stephen Harper set up a public-private partnership fund. For the most part, Professor Siemiatycki said, it has generally worked well.