I thought, Finch LRT will be cheaper to operate than the bus it replaces. More riders per driver, fewer drivers needed, means lower cost.
As we covered before, it's not so cut-and-dried.
In terms of direct operating costs - fuel, salaries, etc. - yes, LRT is cheaper once a certain ridership threshold is reached.
But if you factor in the indirect operating costs - maintenance being a major one - the metrics change quite a bit, as LRT has way more infrastructure directly attached to it (versus a bus that isn't paying its own way in terms of damage to the road). But it's not necessary completely skewed one way or the other, either.
Not so sure about Eglinton, underground stations cost more to operate. But even then, ECLRT almost fully replaces the busy Eg East bus #34, and shortens #32, 54, 56, and 100. The shortening affects the central, congested part of Eglinton from Mt Dennis to Don Mills, where the traffic is slow and a lot of buses are getting tied up today. That replacement should at least help with the cost balance, if not turn it outright profitable for the TTC.
Again, it's not so cut-and-dried. And maintenance is a big problem of it.
About 10 years ago, the TTC reported that it cost them on average $7mil per route/kilometer of tunnel per year. (This was taking into account the then 60-ish year old tunnels under Yonge St., the considerably newer ones under Sheppard, and before the TYSSE was opened.) That was for just the maintenance of the tunnel and everything inside of it except for the trains - signalling, power distribution, life safety, rails, waterproofing, the works. I'm sure that using that number you can figure out pretty easily what level of ridership needs to be achieved on a yearly basis just to cover that cost - and that's before you take into account staffing, rolling stock maintenance, traction power, etc.
Extrapolate that to Eglinton. Sure, the tunnels are newer, and they're not going to need that $7mil level of maintenance each year for a good, long while. But the level of maintenance that they will need will not be zero.
Dan