[… regarding buses …]
Is that really true? Including the necessary maintenance and rebuilding of the rails and the overhead cables?
Yes.
Energy-wise it's quite a bit cheaper.
https://bathtrams.uk/the-most-energy-efficient-mode-of-public-transport/. Trams don't require charging infrastructure and battery replacement or regular refuelling and oil changes in the case of diesel.
Bus advocates love to point out that infrastructure costs are lower, but in reality it's a hidden cost as it gets paid for in regular road maintenance. The problem with that is
buses put a much bigger strain/wear on the roads themselves. Especially when fully electric normal-length buses can weigh in the area of
20,000kg. If you have a route busy enough to contemplate running a tram, then you're going to be running many more buses on a regular basis, likely articulated buses as well (even heavier). Without things like concrete pads, you will see road indentations and potholes formed around bus stops and traffic lights, and these routes will end up requiring more frequent paving, etc. It just goes on the regular infrastructure line of the city budget instead of the public transit line. Just because the cost isn't inherently visible doesn't mean there isn't one.
Tires alone cost the TTC
over $5.5m per year.
If you're going all-electric for buses, then you'll also need to purchase extra vehicles to cope with the route, as buses will need to be cycled out to charge. Though the TTC uses higher-speed pantograph charging on at least some of their electric buses so it's not taking hours upon hours (likely in the area of 20 minutes), the faster you charge a Lithium Ion battery, the faster you shorten its life. The cold winters and hot summers of Toronto will undoubtedly have a negative effect on lifespan. While the batteries are expected to average about 10-15 years (about the expected lifespan of the vehicle), you'll see at least some needing costly replacements before then.
BRTs are maybe an option, but I think that's harder to justify in a downtown core. And if you're doing a separated route anyway, why not put forth the extra capital for tram in order to lower your future maintenance cost?
We're doing all of this tram and subway maintenance at once right now, precisely because we have the first mayor in over a decade who actually wants to prioritize transit and fix the problems we've been ignoring for so long. It doesn't help that it's coming at the same time that Metrolinx is digging up the core for the Ontario Line.
The lack of funding is real enough and has been for a long time. So is the political football around announcing new investments. So given the resources TTC has and expects to have, is there really a good case for building new street level rails, and not for example dedicated bus lanes?
Yes. Overall lower costs.
"The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money. Take boots, for example. ... A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of OK for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. ... But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that'd still be keeping his feet dry in ten years' time, while a poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet."
–Men At Arms, Terry Pratchett