There are a number of other renders posted on the City website now. Along the right hand menu.
http://www.winnipeg.ca/publicworks/c...s/cprYards.stm
They have variations of the bridge. From a basic steel girder bridge to one of the fancy arch truss bridges. It looks like the centre span is longer.
If they go with the basic steel girder bridge, the entire bridge and bridge approaches will need to be higher to make clearance. If they go with the arch or cable stay, they can reduce the overall bridge height. Due to that centre span being the longest, it would need the deepest girders.
It could be cheaper to go with some kind of arch. The bridge approach will likely be MSE. They'll use some type of lightweight fill which can get expensive on high embankments. MSE is the approach of choice these days as it greatly reduces settlement, to almost nil in most cases. So whatever combination gives the lowest overall cost should be the solution.