Why is this not what we're aiming for?
Ok, I'll bite.Quadruplicate the ENTIRE network.
This is ridiculously simplistic. Where to begin? For a start, many sections of the network already have 4 or more, do you suggest we make these sections 8 tracks or more, or leave them as they are? Secondly, there are many parts of the network where the alignment simply isn't wide enough to quadruplicate without compulsory acquisition of properties and public spaces (for example Footscray to Newport) or major earthworks (for example Upper Ferntree Gully to Belgrave). Thirdly, Why does the whole network even need to be quadruplicated? I can't ever foresee a need for 4 tracks between say Greensborough and Hurstbridge for an example.
On the other hand, Caulfield to Pakenham, Sunshine to Sunbury or Melton, yes, that has practical merit and is even realistically doable. Partially reinstate Jolimont Yards.
Where do you suppose there is space for this? The land that the former Jolimont yards was on is gone, there are apartment buildings and a tennis centre in that location now. Do you propose we demolish these?Double Deck Flinders St.
Why? Isn't the purpose of the Metro tunnel (and the proposed Metro 2) to untangle the network and decentralise so that not every single train starts and ends at the same point creating a mass bottle neck? Doesn't this negate the need for increased capacity at Flinders st?
Even if it didn't and we were to follow your inane plan of "Double decking Flinders St" How would that even work? Would you go down and have another 10 platforms underground (ignoring the fact that Flinders St is right alongside a river making it quite difficult to go underground in this fashion) or would you go up, placing another level of rail tracks above the current level, in which case it is hard to see how you could design such a station in any way that wouldn't see the entire destruction of the current station, which is one of Melbourne's most beloved icons.
And of course, all of that goes without mentioning the most obvious problems with your nuts plan:
a) How much would it cost?
b) How big of a workforce are you going to need on top of those already deployed on the multiple other infrastructure construction projects around the state?
c) Who is going to pay for it?
d) How much disruption is your master plan going to cause?
I look forward to our OP not bothering to reply to any scrutiny.
Now I need to take a shower to clean off the foam.