I've got something very similar.
CPKC new route north of City is ~30 miles. Old route through City is ~27 miles. CN new route south of City is ~28 miles. Old route through City is ~24-25 miles depending which line you use as your start point.
CPKC will not go around the south end of the City. The route is too long vs existing. The CPKC route utilizes the existing CEMR track right of way from north Transcona through East St Paul to the Red River. This uses the existing floodway bridge, but requires a new Red River Bridge.
Through West St Paul the ROW is threaded through the residential at Seiler Road, west of PR 220. From there it's westward along one of the grid roads. It could be moved to maybe on the 1/4 line so it's in the middle of the fields. Either way, the route is there. New yard up in Rosser somewhere. I didn't spend much effort at the west end
CN my route starts at Plessis and PTH 1, on a new corridor south across the floodway. New floodway bridge and new Red River Bridge. CN will be picky here on what they want. They never want a longer route, based on travel times. So coming out of Symington, this provides the shortest stretch to get down around the City. They'll probably want a connection from the existing main track near Deacons south of the floodway to my blue alignment as a direct bypass.
CN Transcona Yard would utilize the existing tracks between Plessis/ Lag, etc to get down to Symington and to the new corridor.
South of the floodway, I threaded the new corridor through the residential. There will be some properties that need to go. To the west, I spent little effort, but the tracks will need to just cross cut the farm lands for the shortest route.
The further out you get from the City to avoid residential the longer the route gets. Any of the options need 2 new Red River Crossings, likely a new floodway crossing. Grade seps of PTH 75 and potentially many other highways. 2 new 30 mile long double track signalized corridors for the main track. Expensive. New CPKC yards, etc, really expensive.
There will still be tracks heading into CentrePort, there will still be some other industrial tracks need int eh City. But for the most part, all of the main traffic will divert around the City. We can't just completely remove every spec of railways, that's not the intent of this. It's to move the bulk of through traffic out of the City.