Something worth thinking about here could it be that the State Govt still has plans to turn the Outer Harbor line into light rail. There is a chance this could be part of the plan actually.
The state Government in recent transport plans for the tram have said that they plan to build 100 metres or so of Tramline down in front of Festival Theatre. As well as building it along North Terrace in an Easterly direction.
Now later on you take the tramline and extend it down to War Memorial drive to service Adelaide Oval and then build a tram line along War Memorial Drive to almost where the new Dive under for the Outer Harbor line is being built. Convert the now broad gauge tracks on the whole Outer Harbor and Grange line to Standard gauge by simply moving one rail into the inner most position on the sleepers. Now at War Memorial Drive at its closest point to the railway line it could then be connected to this track that has been converted and go down to the new station at Port Adelaide and then go out into the street there and then curve around the courts and police building and then proceed down St Vincent street in a westerly direction towards the Jervois Bridge.
Either go over the existing bridge or build a new tram bridge alongside it and then by doing a bit of street running through Ehelton and Glanville come back and pick up the old rail alignment at or near Glanville with a spur line down Semaphore road if needed still. The other tracks then go all the way down to North Haven and stop there. Outer Harbor would not really warrant going to though.
This would allow the current overhead bridge, station, viaduct and embankments to be flattened and sold off. The railway line then from Port Adelaide Junction to just out of Glanville could all be removed then.
Oh and the Grange line could be made to go to West Lakes if needed and the tram could go over both lanes of Port Road on a over head bridge with a stop on top of it similar to the South Road overpass but built and designed a lot better.
This could be why a double track is slated to be built at Port Adelaide as only one platform is actually going to be provided there and also the tram would take you right into the centre of the Port Adelaide CBD area as well. Could this be the state Governments master plan though.
Check it out on Google Earth or similar it can be done and with very little new bits and pieces needed as most things have now been done or going to be done soon to do this like the new bridge at South Road on the T2T project.