Old, as in mid-2010s. I thought they reopened it with those 4 options, that they'd had an alignment a decade before that (perhaps that is blue).
They've been studying this since at least the 1970s. Studied to death, the Star reported in 1987! How does this compare to the 4 routes examined in the 1987 Dillon study?
The outcome of the 1987 study was choosing a route that's similar to the currently proposed route, but using a new alignment in Oshawa between Thornton and Stevenson rather than using the GM alignment. The blue route above from the mid-2010s used a new alignment that is further west - in Whitby.
Here's the "finalized" route map that GO released in 1988. It was supposed to open by 1991.
View attachment 583058
I wonder how many alignments there have been since the 1970s.
And the alignments keep getting worse and worse. Recall the early 1980s proposed GO alignment diverged from the CN tracks at Whitby GO, following the 401 to Hopkins, and then a very shallow tangent to the CP tracks, joining them just east of Thickson. I'm not sure that's even possible now, after they instead widened the 401 - and with all the development now between the tracks.