Comparing Tokyo Metro vs Toronto's subway system: is the Toronto subway really unprofitable?
The TTC subway is not profitable in the corporate sense that it requires zero government funds going in and pays a reliable 5% to 10% dividend per annum out with expectations of paying back initial principal too.
The total cost of running the subway is operations (say $200M/year as a very low-ball estimate), a minimum of $400M per year (SOGR budget for rolling stock, signals, tunnel repair, storage yard expansion/work, etc.), plus initial capital outlay. TTC states their assets have a book value around $10B and you can assume a majority of that ($8B) is the subway tunnel/station infrastructure.
Even just determining it on an operations basis is difficult.
If you canceled all feeder bus routes then subway revenue would be severely impacted. Allocating funds for one part of the trip to one component and stating it is profitable and that the bus loses money isn't functional since we cannot actually eliminate that cost; and that's if you come up with an agreeable split. You can split revenues based on time, distance, operating cost of the segment, importance of that segment to the rider, equally based on number of segments, or any number of other ways. These will all impact the profitability, or not, of the individual segments.
I'm pretty certain that the TTC and Mississauga use different calculations for splitting revenue. There is no standard way to do this.
Second, what is an operations expense? You can buy a fare processing system as a capital expense OR you can lease it. You can buy the office building or you can lease it. One is capital and the other is operations.
Many firms prefer to put lots of things under operations that TTC puts under capital. Many airlines lease their aircraft (nearly all airlines lease some) and do not buy them for example. TTC can package up many small operations outlays into a single large capital project which they can convince the province to fund (see signal system overhaul which is development of about 3 new signal systems and dozens of supporting components).
Even some of the regular vehicle maintenance is a capital expense at the TTC through their interesting use of vendor warranty programs. They pay the vendor as a capital item and have the vendor pay the TTC maintenance guy on the operations budget. That 70% farebox recovery number is misleading at best.
Again, there is no standard amongst transit agencies for handling the capital/operations split and few push as much onto capital expenses as the TTC.
If the province suddenly decided to fund 75% of the operations budget and zero captial dollars you would find the TTC leasing TBMs and hiring contractors on a cost-plus arrangement for constant expansion, getting rolling stock as a service (1000 functional vehicles available daily; vendor provides vehicles and performs all necessary maintenance), leasing storage yards instead of buying them, etc.
The capital budget could be brought down close to $0 with a sufficiently large operations budget. Likewise, a preference can be made toward capital cost when funds are available there.
Profitability can only be measured on an overall basis because the numbers can be fudged any other way.