It's not required at Sunbury as the location of the sidings makes it easy for Metro trains to shunt out of the way of those run by V/Line. The location of the sidings at Pakenham makes this move a lot more complex.You are correct.The Pakenham East Skyrail proposal looks quite good. Especially the separation of V/line and Metro trains.It might look good, but is it actually good?
The question is why the need for a station at Pakenham East? They'd be mad to build it on the down side of the entrance of the Pakenham East maintenance facility as it would require unnecessary shunt moves for terminating trains, and then you might as well continue the short distance around the corner to Nar Nar Goon where there's plenty of room for car parking and existing access to the freeway. Its not going to be built on the curve under the freeway which then leaves the only location as just on the UP side of the freeway overpass which is within spitting distance of the existing Pakenham station anyway.
Now anyone with access to google maps can see that on the UP side of the freeway overpass on the North side of the line around Pinehill Drive and Ryan Rd, its all very low density housing and on the South side is small industrial area which isn't going to generate many trips. The large open area on the North side between the railway and the golf course is a reserve and water retarding basin, so that's not going to be developed anytime soon.
So after all that, my theory is that the new Pakenham East station is being built primarily for operational purposes for Metro and the HCMT. This thread from back in 2018 https://www.railpage.com.au/f-p2113207.htm explains a bit that non-qualified drivers such as fitters can and will be moving trains around the Pakenham East facility and doing preps and so on. The new station would provide a transition point between qualified drivers and fitters etc and could possibly even be built within the facility to avoid any disputes of non qualified drivers driving on the mainline. Looking at google maps at the Pakenham East facility, at the West end there is a dam with two tracks just to the North that look very unusual in that just before they finish in a dead end they come close together as if there should be a point installed. Earth works also suggest that it was going to be or will be extended so maybe this was there plan all along?
Its a bit of different theory but I personally can't see any reason for a station at Pakenham East and details of the why's and where's seem to be non-existant.
A Metro Station Master has confirmed that the only reason PKE Station is being built is so drivers can get to PKE Depot. I imagine this to be more of a changeover, any remote/automatic shunting will be confined to the depot. Completion is marked for Q1 2023. It does have the added advantage of moving the track work away from Pakenham and I'm sure it will be surrounded by houses a year or so after it is built.
The station its self will most likely sit opposite the Depot to allow easy access for drivers. Where is the question as any new station would need an access road from Oakview Lane or Bald Hill Road. It's quite possible that like most 'Sky Rails' LXRP and Council may be looking to activate the station area with a new park or public plaza. This would make the new PKE Station prime for a large park and ride facility.
The release says that 'metropolitan rail track will be extended by two kilometres', meaning from where it currently ends at Pakenham. This puts the new station on the up side of the Freeway.
The platforms are clearly operational only - Level Crossings does not want to build crossovers on the viaducts, and Metro wants somewhere to turn back the HCMTs without V/Line interference. Given that involves some track amplification, don't expect it to be any longer than it needs to be to save money.
There has never been any mention in any planning documents about a Pakenham East station, and the Pakenham East plan shared was done with no idea it was on the cards.
Really this is just another aspect of putting something that should be part of the Metro Tunnel project off to another authority to keep the books as light as possible. The real question is why Level Crossings aren't taking the same opportunity at Sunbury to try and remove some of the V/Line conflict there.