officedweller
Senior Member
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The level you currently use at Queen St. Station, to get from the SB to the NB side and vice versa, is, in essence the platform level for the Queen Street subway (likely streetcar subway) that was constructed at the same time as the original station, as it was thought at the time that an E-W line was likely to run under Queen.
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This image below is from BlogTo:
View attachment 355130
Credit: BlogTo
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Just thought I would share that the above is likely a part of the story.
So chances are that what I marked as "Transfer Level" is a renovation of the lost Queen Subway station rough-out to expand beyond the current underpass corridor
(maybe installing raised floors in the areas originally designated for streetcar tracks) and maybe, as mentioned above, the big white void area is intended to retain support for that old infrastructure.