no, they simply want an additional track past the UPx spur, which IIRC was the terminus of the Georgetown South EA.
I went looking today for the source documents behind your quite correct recollection. This little adventure got me ranting:
The GO Transit and Metrolinx web sites do a very poor job of archiving the various EA's when commissioned, and of tracking for us taxpayers whether they have been completed and finalised. Or, for that matter, whether they were acted upon. This is one of the reasons why it is so easy for these agencies and their political masters to rewrite history and set off in new directions - leaving the old ones buried.
First, here's a presentation from 2006 which does establish that as far back as 2006, everybody was focussed on the airport line first and Georgetown second
http://www.gotransit.com/gts/en/resources/archive/pic/go_pic_presentation_final_june21.pdf
But..... here's a 2002 document asserting that a study will provide the full assessment for the line to Georgetown at least
http://www.gotransit.com/gts/en/resources/archive/other/GO_Expansion_EA-Report_Draft-Rev6.pdf
And here's a 2009 commentary by Steve Munro, quoting (accurately, I'm quite confident) Gary MacNeil who states that the EA for the expansion all the way to Kitchener is complete and ready for approval (but - also that improvements for Georgetown GO aren't a priority before 2015)
http://stevemunro.ca/2009/10/27/go-transits-service-plans-small-changes-now-more-later/
And, of course, there is in fact an EA report
http://www.gotransit.com/public/en/docs/ea/georgetown-kitchener/rail_expansion_esr.pdf
Lastly, here's a 2013 commentary by a Brampton Councillor about the whole thing:
http://www.bramptonguardian.com/new...-service-derailed-by-big-business-councillor/
My own recollection knows that I have seen a GO powerpoint presentation showing the exact proposed alignment of the third track through central Brampton (it is controversial, because it proposes removing the current Depot, a heritage structure). So there was likely the start of an EA on that part specifically.
My point is - Call me anal but I would like to see a properly indexed, searchable, and sustained archive of all the projects that GO initiates. So we can see where they are driving to completion, and where they have lost the thought and moved on. There's a lot of "ready, aim, aim, aim....." in this file and not a lot of forward movement. And a lot of promises forgotten.
PS - If I am simply missing a link to an index that actually exists on these agencies' web sites, please tell me and I will gladly admit my folly.
- Paul