Reading through the Staff report of December 16, 2009, I see that the hole for the Campus Station will likely also be the recovery pit for the TBM. This pit will be in the space-restricted area between Nicholas and Colonel By, with a vertical retaining wall of about 23 metres beside Nicholas. This is almost an 8-story retaining wall!
I do not believe that Nicholas can not be affected. At best, it will be reduced to two lanes, at worst, closed entirely. I found a representative picture of a european station being built:
The duration that this cut will be open will be quite long as it needs to be there when the first pass of the TBM is complete and at the end of the second pass. Only then can the station begin to be built. This will affect Nicholas for probably 2-1/2 to 3 years. And don't think that you will simply use Colonel By as an alternative, since it will likely also be closed during this construction.
Of course, the closing of Nicholas would be a great time to work on the Cut & Cover tunnel that needs to cross Nicholas and Mann to get to Lees Station. Again, a representative picture from the Web:
The biggest problem is going to be when this Cut & Cover operation gets near the east portal because that is too close to the Transitway turn-off between Lees Station and Mann. Remember that the Portal cut will still be about 13 metres deep. There are only a few metres between the two so once the tunnel work gets close to the portal, buses will no longer be able to use the turn-off to get to King Edward.
Instead, buses will need to use the access which passes beside the tower next to the Station. This will mean that all buses will need to rise up to Lees Ave. to sweep over the 417 to get to King Edward. This will probably lead to the need for a traffic signal at the intersection of the Transitway access and Lees Avenue.
Traffic- and transit-wise this plann is VERY disruptive.