Well, see, if you amortize the capital costs over a certain period of time, you therefore determine the annual cost of running a public transit system operating on amortized capital, and then you take the portion of that cost recovered from fares--there should be some, even if it's a very small number, maybe 10% or 15%....
I'm just wondering if there's any accepted fare recovery threshold that determines whether something is or is not a good investment.