Calgary did it successfully, and crams 300,000 people per day through one downtown corridor with level crossing intersections downtown.
And, in 2020/1 thru 2025, we are doing it in Hamilton -- look at what we're doing with Hamilton LRT!
Two-coupled LRVs in a Toronto King Street Pilot style corridor! We're putting essentially a double-length streetcar into our own King Street here (a 1-way car street), kicking cars off 2 lanes of street. If we are about to do that, so probably can Toronto (eventually -- at least in a 25 year time window, post condo-densification).
Granted, there's quite a bit of prep needed
1. Dealing with side streets. We're banning left turns from all non-signalled side streets.
2. Curbing off the LRT lanes all the way between signalled intersections
3. Addition of appropriate transit priority systems at the signalled intersections.
It won't happen today but could happen within 25 years to eventually King turned into true-LRT corridor end-to-end, once the following happens:
A. Several LRTs gets built and Toronto residents "finally get it" (streetcar path to true LRT) and starts demanding/voting towards it.
B. Superdensification continues for another 25 years.
C. True transit priority optimization (0.5km curbed + true transit priority + leftturns curbed-off at all non-signalled intersections + farside stops)
D. Funding happens at least one level of government to make it happen
True metro-speed (non-metro but still metro-speed) surface transit can succeed with:
(1) Car-free tracks
(2) Far-side platforms so streetcars coast through green lights before picking up passengers
(3) Reliable green-light transit priority; which requires:
(2a) Left turns blocked-off from minor side streets
(2b) Plenty of curbed-off coast distance between surface intersections, about 0.5km-ish
(2c) Allows enough time for countdown crosswalks to finish before green light to let full speed streetcars reach their next stop reliably.
This is the metro-speed metro-frequency non-metro system used elsewhere in the world:
<LOOP>...Streetcar accelerates from previous stop. Complete curbed stretch all the way to next stop, nothing blocking the way. Streetcar arrival at next traffic intersection hereby predictably predicted. Beep. Now, 0.5km away atthe next traffic light auto-adjusts next timing. Its crosswalk countdown begins appropriately well within Ontario specs.....tram/streetcar/LRV approaching....countdown finished....traffic intersection clear for the rail....green light for rail.....5 seconds later....WHOOOSH.....streetcar whooshes through intersection.....and decelerates at the far-side platform stop.....majority of deceleration primarily for stops even at peak period......rinse and repeat.....</LOOP>
Toronto has not yet upgraded to this transit priority system, but they're being used NOW, already, TODAY, elsewhere in the world.
The design system of "farside+spacing+predictable" logic that allows reliable metro speeds both offpeak+onpeak of much more reliable green light transit priority systems. Some of them intelligently stretches the green light period for cars when it knows no streetcars are approaching for a while, so it can smartly compensate for the well-timed green lights by smarter design with the within-safefty-margin of lengthenings/shortenings (within specifications) of green/reds with no interference to crosswalk countdown lengths.
Many peasants see "transit priority systems" and wonder why they don't always work well. Look closely. Some of them work spectacularly well and others don't work well at all. And I am here to tell you -- most of Toronto's transit priority systems is crappily designed. But they won't always be permanently that way; given the societal path, demographics, ever-expanding downtown transit needs, continued superdensification, familiarity with other Ontario LRTs, etc - eventually something gives, and people are going to increasingly ask "why isn't King doing it?" Then ten, twenty, thirty years later, the domino falls....
There are solutions for intersection blockages at peak -- e.g. cars that creap through. Some of them use traffic-blockage cameras to enforce "keeping the box clear" so that intersections are not blocked when it's red light for cars.
These kinds of solutions are cheap, it's already being done, and it already pushes 6-figure people per hour through surface intersections, and Toronto can do it, full stop. It's just a matter of time when the resistance buckles and it happens -- whether be 10 years, 25 years, or 50 years, thanks to superdensification and the need for a low-lying apple metro-speed metro-capacity route even if it is a non-metro route. As long as a city is (eventually, grudgingly, slowly) willing to give up some car capacity on a specific street.
We'll still need all the other stuff (RER, Ontario Line, etc) but that's no reason to not consider upgrading a streetcar route to 6-figure ridership per day. It's done, it's doable, and it's simple transit-corridor engineering.
At some point it's quite possible:
2025: They rebuild King corridor to a transit-only corridor (urbanization)
2030+: Building owners start slowly building alternate accesses and solutions
2040: Curbs added and fully ban all vehicles (except emergency vehicles), ban all left turns except at signalled intersections, etc.
2050: Phase 2 rebuild of King extends to 60-meter 2-LRV and raised level boarding platforms.
Or some kind of similar progression, whether be 2040 or 2140. I think it's inevtable given Toronto's superdensification status, Canada's favoured-country status, and the infinitely increasing demand for transit in the coming decades. It won't happen in a few years or even 10 years, but, it's a pretty damn obvious low lying apple in humankind progress this century to gain a metro-speed metro-frequency non-metro route.
In short -- the continued superdensification plus the upcoming big boom of Ontario LRT to inspire residents to vote for the true King LRT eventually.
For less than a billion dollars -- metro-frequency metro-speed "non-metro" surface route that becomes true rapid transit in speed. Even faster and more reliable than today's King Pilot (and that's without raising speed limits for streetcars).
I do drive a car and I understand "You'll take my car keys out of my dead hands" mentality on keeping King accessible to cars -- however, we're already successfully pushed through a King Transit Priority (Phase 1). What I am talking about is really Kind True LRT (Phase 3) stuff. long after the King First Rebuild (Phase 2) stuff that does initial things like build streetcar stops with curbs stretched all the way out (possibly even raised to level boarding to 1 streetcar), rebuild the sidewalks, etc.
Again, the 2-LRV consist stuff would only be be two King rebuilds later.
There are cities in the world that accomplished 6-figure ridership on a single downtown surface rail route. The huge gain in capacity this affords (especially with raised level-boarding platforms, ION LRT style and Hamilton LRT style), is already an option once Toronto is slowly eventually ready to optimize this corridor.
Step 1: elect real pro-transit politicians (both MPPs, Councillors, and Mayor)
Step 2: get real pro-transit bureaucrats, who will not put up roadblocks to stifle transit and pedestrian improvements.