G'day all.
What about full duplication of the Crimebourne line with an extension to Clyde? Also the long awaited (almost) forgotten third line from Caulfield to Dandenong.

3rd track Caulfield-Dandenong has had the kibosh put on it, courtesy of the idiotic decision to build 'Skyrail' (CTD) as duplicated track instead of provisioning quadruplicated track.

The Skyrail design permits quadruplicated track between Oakleigh and Dandenong.

Though Clayton an additional double track viaduct would be built over where the railway alignment Is now (South of the viaduct currently under construction) , same thing at Noble Park, though at Chandler Road the viaduct swaps sides (the second viaduct can ease out this slew their making)

Caulfield to Oakleigh well that's In the too sticky basket at the moment.

Property acquisitions
Noisy protest
What to do at the Frankston line Junction

The design itself might, but it will be politically impossible for the next 30-50 years to do anything else to the Caulfield-Dandenong corridor, so nothing will be built. Any changes to the parkland they're creating down there, and the government would be toast, so they wont touch it at all. Infrastructure Victoria has backpedaled away from wanting four tracks, which I assume is a Political direction, because even with High Capacity Signalling the mix of Metro, Vline and Freight Services is never going to allow the frequency and speed they need.

Looking at the area map for Caulfield-Hughesdale, it looks like the only options will be property acquisition, or building the new viaducts down the centre of the other two, ruining the parkland.

I really think this has been largely a mismanged project and should have been better coordinated with and a part of the Metro Tunnel project to give the best outcomes across the board for the Metro line and Gippsland V/Line, who have largely been ignored in all this.

Yeah, the more I weigh it up, the more I am confused about how they intend to expand the track capacity?
Will people be angry if they 'double stack' the existing viaducts and add additional tracks above the viaducts?
Will people be angry if they slot more viaducts next to each other and absorb the parkland they've just created?
In terms of the pre-existing trenches along this corridor, would they simply add another trench alongside the existing trenches? Would they slot viaducts along the alignment of the tracks pre-trenching?
Whilst this project may hamper the ability to run additional services for a while, because it will not be possible to add more tracks, will money talk and the 'Bay West' project force the future ministers to consider expanding to at least a third bi-directional track?

You could avoid the cramped Oakleigh - South Yarra section by rebuilding on the alignment from Hughesdale to East Malvern and then run into the City via Burnley. Trouble is, that line is already busy with its own traffic and would need to be quadruplicated to create any time competitiveness with the current main line.

The design itself might, but it will be politically impossible for the next 30-50 years to do anything else to the Caulfield-Dandenong corridor, so nothing will be built. Any changes to the parkland they're creating down there, and the government would be toast, so they wont touch it at all. Infrastructure Victoria has backpedaled away from wanting four tracks, which I assume is a Political direction, because even with High Capacity Signalling the mix of Metro, Vline and Freight Services is never going to allow the frequency and speed they need.

If you follow the rants of the anti mob, they well and truly accept that more than 2 tracks are going to be used on the Dandenong line, as they criticixe the LXRA artist Impressions pictures for not Including the 2 additional tracks, 12 years time Is the number they throw around for development of the 2 extra tracks.

Then of course many people are puzzled and question as to why 4 tracks are not built first up, simple answer to that Is lack of funding (Governments are too focused on funding to add more lanes to the Monash)

Yeah, the more I weigh it up, the more I am confused about how they intend to expand the track capacity?
Will people be angry if they 'double stack' the existing viaducts and add additional tracks above the viaducts?
Will people be angry if they slot more viaducts next to each other and absorb the parkland they've just created?
In terms of the pre-existing trenches along this corridor, would they simply add another trench alongside the existing trenches? Would they slot viaducts along the alignment of the tracks pre-trenching?

There sure won't be any double stacking of viaducts ! (land In Melbourne's middle suburbs not worth that much)

Springvale Is the only trench between Caulfield and Dandenong, It would be fair to say the trench would be enlarged (South of the existing one) to keep In with the local street / station scape (though an elevated viaduct would be much cheaper and easier to build with minimal closures of Springvale Road)

For me with regards to Brighton Beach i would grade separate Hampton and Sandringham and provide two platforms at Sandringham, this would be all underground
I would stable three trains at Brighton Beach  with the third track
Middle Brighton is not all that necessary
You mention the Doncaster Line and hasn't the last already been sold on the Eastern Freeway

I rarely visit or post here, but seeing as I've become well acquainted with people in the field of late, I thought I'd present what they (and I as it turns out) think needs to happen with Melbourne's train system:

- Complete signalling and control system replacement.
- Duplication of every single track section of the electrified network (with triplication/quadruplication where required).
- Reconstruction of every other track section.
- Remove EVERY level crossing.
- Running a shuttle tram through the Altona section.
- A new train line through Werribee South/Point Cook through Newport/Fishermans Bend terminating at Doncaster East.
- An airport rail link running from the airport through to the Showgrounds line (via Highpoint) through dedicated tracks through the CBD then running through to Rowville East.
- An outer orbital rail line of sorts running from Frankston through Box Hill then under Bell/Burgundy St then linking up to the RRL.

The only reason the CBD is a hub these days is because there are no viable alternatives to avoid it. Circumventing the CBD would reduce the load on the system immensely as a fair whack of the patronage doesn't have the CBD as the destination. Melbourne Metro is one step to remedying this.

What this really needs is SUA   (stop using acronyms).

I'm sorry but the rail industry or transport industry in general is full of acronyms. It's sink or swim.

I can make a Glossary in this post.

The Train Protection & Warning System (TPWS)https://en.wikipedia.org/wiki/Train_Protection_%26_Warning_System
Automatic train protection (ATP)https://en.wikipedia.org/wiki/Automatic_train_protection
Communications-based train control (CBTC)https://en.wikipedia.org/wiki/Communications-based_train_control
SELTrac https://en.wikipedia.org/wiki/SelTrac