Highway 7 - Kitchener to Guelph

[Viewfromthe42]

I don't think replacing the rail bridge is in the plans as previously mentioned, however the only likely scenario I see would be to build a single track span, demolish the old double track bridge followed by twinning the new bridge over the old alignment. This would provide a double track bridge offset by a track width which should be able to be accommodated at either end. This could also work nicely if the need for a third track comes about. 

Rail Bridges need to be much stronger than a vihicular one therefore I can't see a temporary span working here.

Yes and no. Have a look at the form of the Weber rail overpass, which doesn't have people or cars running on it, and see a very simple metal bridge that you couldn't get away with for cars or people.