Publicly-used facilities typically delivered and financed through PFI, PPP and concession structures, with availability-based, government-backed revenue streams.
Social infrastructure is the purest expression of contracted infrastructure cash flow. Most of the class is delivered through availability-based PPP/PFI structures: a private partner finances, builds and maintains a public facility, and is paid an indexed government annuity for keeping it available to standard, with no demand risk, only performance deductions. The result is a long-dated, inflation-linked, investment-grade cash flow.
The exception is operational real estate such as student accommodation, where revenue genuinely depends on occupancy and rent. The references below set the availability model against that demand-driven outlier.