The TTC projected that the 3.5 km LRT extension between Renforth Gateway (at Eglinton) and Pearson
would have 500 alightments and 0 boardings in the peak hour. This extension is estimated cost around $300 Million, and that's assuming that it's built completely at grade without any specialized structures, such as bridges or tunnels. We didn't complete a TPAP for the Airport lands, since that is the jurisdiction of Transport Canada, thus we don't have a good idea of what infrastructure is required to build the LRT extension to the airport. If it is indeed true that specialized structures would be needed, the costs could easily escalate to $500 Million+ for the 3.5 km LRT extension.
That said, looking at the geography of the airport region, I can't envision how the 3.5 km LRT extension to the airport could be built completely at grade. The planned terminus was Terminal 1, with a connection to the Link train. At this location there is no suitable road space for the LRT to utilize, nor is there any room to built an LRT corridor at grade. The terminus of the line would likely have to be elevated to connect to LINK and Terminal 1. There's also the challenge of navigating the web of overpasses that surround the terminal, which will pose its own set of engineering challenges and additional costs. With all this considered, it's probable that we'll see large cost escalations for this segment of the line. It's hard to justify this extension with such low ridership, and high costs.
My preference would be to have our 192 Airport Rocket route add a stop at Renforth Gateway, where commuters could transfer between the 193 and the Eglinton Line LRT. The 192 Airport Rocket is would be able to handle the demand of 500 peak hour alightments very well. The transfer wouldn't be the most convenient option, however the magnitude of the inconvenience caused by the transfer is reduced when considering that we'd likely have every second Eglinton Line train terminating at Renforth Station due to the drop in demand north of there Renforth (Eglinton Line loses 50% of its westbound/northbound peak ridership at Renforth). The 192 Airport Rocket presently operates at 10 minute frequencies, all day, towards Pearson, and Eglinton Line would likely operate at 7 to 8 min frequencies, at peak hour, towards the Airport, if that 3.5 km extension between Renforth and Pearson were built.