And rerouting freight trains to free up the tracks won't deliver the same benefit?Go put a price tag on your grand plan the shut down Dynon / South Dynon rail yards along with Swanson Dock, Appleton Dock and Victoria Dock, all to massively expand Webb Dock (of witch property developers want anyway for their Fisherman's Bend urban re development)
Along with building a expensive freight train tunnel under the Yarra River and Newport.
Building new rail freight terminals (to replace Dynon yards)
What do you gain ! exclusive access to a few km's of goods line between North Melbourne and West Footscray wow !