The real tragedy here is that UPX could have been Toronto's first S-bahn type rail service, if it only had accepted TTC fares for travel inside Toronto, and charged a premium for boarding/exiting at the airport.
No, it couldn't have. Not with the budget and timelines that were available in 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011...
A door-to-door Union-to-Pearson S-bahn would have needed far more capacity in order to accomodate the non-airport traffic. That means either longer trains (ruling out the relatively inexpensive station that was dropped in at Pearson and instead forcing them to do something bigger and probably underground) or much shorter headways (making the corridor works way more complicated and pricey).
On that latter point, we've been over this a few times in this thread with various doodles, but without coupling it to a transformation of mainline railway train control (ie cab signalling and PTC) to allow the Euro-style headways that we're still not sure if GO RER will be able to pull off in 2020, probably the only way that could have been done in 200x was by turning two tracks into a completely isolated non-Transport Canada-spec rapid transit line and permanently hobbling all the 905 GO services and Via (and HSR?) services by confining them along with freight to a remaining tight stretch of land that might be a real squeeze to upgrade even to double track. There'd also need to be a totally new and expensive downtown terminal separate from the existing Union Station corridor.
As more stops were added to the line, travel time would rise and that "get to me to the airport, the 192 doesn’t cut it" ridership segment switches back to cabs and drop-offs and the like. When combined with longer/more frequent trains that would probably leave a heck of a lot of empty seats for the last leg of the line into the airport on some potentially overbuilt infrastructure.
Finally, where the heck would the operating subsidies required to run at a TTC fare have come from?
This was a real missed opportunity, but can still be done if the political will is ever there, or the residents along the line begin demanding it. How will it feel when residents realize they have a frequent train service running through their backyard that they can't afford to use, and have to be satisfied with shitty bus services that really make reaching downtown a mission.
There is political will to run RER service on this corridor. We don’t know if it would stop 4 times or 8 times or whether there would be a single evolved-from-GO service or whether there’d be a variety of different trains on the line, like a Toronto-local train and a 905-oriented more traditional GO train.
But my gut feeling is that the right approach is to keep the airport train fast and direct and price it higher, and then handle the commuter and everyday trip market with services that are cheaper and keep going past the spur junction to serve Brampton. People heading to the airport willing to trade a bit of time for a cheaper price could take the regular train most of the way there and then transfer to a bus, an APM extension, or potential Finch LRT extension.
Finally, there is a pretty good alternative to shitty bus services to downtown already in Weston… a large green train that already runs at rush hour and sounds like it’s going to offer some kind of two-way service in the near future. That it’s not fare integrated with the bus or that it costs more than the equivalent TTC journey is a separate problem, and one that a hypothetical Union-Pearson S-bahn also would face.
I expect a major uproar from the community once the line enters service.
I think we’ve all already seen plenty of that uproar.
