Thanks for the photo update.
Man is the viaduct ever currrr-vy and those aren't even the tightest turns. Maximum speed is going to be quite slow on that, I'd estimate 30mph.
I would have preferred this option;
1. Use of existing industrial spur connection to the mainline, the switches and track alinement would of course need significant upgrading.
2. Two industrial facilities would be cut in half, they may have been able to continue operations on smaller portions of land. One is an oversized storage yard for Ipex Inc the other Gazzola Paving Limited. May have required expropriation.
3. Gentle high speed curve along undeveloped land.
4. A City of Toronto Winter maintenance depot located here would need to be relocated.
5. Most expensive potion, Disco road would be grade separated with an overpass followed by 6 new bridge structures for the 427-409 interchange. The track however would remain at almost the same elevation, and trains would be able to operated at a high speed as the 427-409 interchange is already at an elevated level.
6. The UPX would continue at ground level along side unused parking lots.
7. The UPX would only now begin to elevate in order to clear Viscount Rd and further onto the airport. Access road to the parking structure would of been relocated to south side.
8. UPX trains finally slow down for the final curve into the Airport station. This path would have required the removal /rebuild of the Airport people mover.
9. UPX continues along an elevated viaduct at a much lower level then the actual one above Dixon and airport access roads.
10. UPX continues next to the T3 parking garage and then follows that of the existing people mover using most of its existing columns.
11. UPX terminates where the Airport people mover station for terminal 2 currently exists.
In all, travel times could have been cut by 3-4 mins from the currently projected 25 min since the almost 2 mile long/3km viaduct will be the slowest part of the trip (the slow trip through the Union Station Rail Corridor is at least only a little over 1 mile long). Likely would of been more expensive option and probably would have required the elimination/rebuild of the people mover as well as some expropriation. But I'm curious if they even considered such an option.
Anyhow, whats done is done.