LancedDendrite, I think the southern route proposed by you is an excellent idea.
May I humbly make a few suggestions for improvement:
1) Would it be possible to build an East Sunbury station, somewhere near the intersection of C325 and C743?. Also, may I suggest North Sunbury station should be built north of Raes Rd (it would then be closer to more residential development).
2) There is a crossing of Shepherds Ln. This seems unnecessary, I would make the rail line cross under C743 south-east of Shepherds Ln - it has to cross C743 somewhere so that is a better place IMHO.
3) Where it crosses Loemans Rd (west of Bulla), the current drawn line is going to need a tunnel to get from 120m altitude to 160m altitude. If the line is moved a bit further south, it can follow the contours of the land at 1/50 and no tunnel is required.
4) All curves on any new track must permit 160km/h - from memory this means the minimum radius should be 1600m. The connection to the existing Albion line should be redesigned so trains could run at 160km/h. Of course, this requires a much longer bridge and is more costly - but when you build something that will last more than 100 years, it needs to be built properly. Also all other curves should be 1600m or greater.
- East Sunbury - Why bother? The only reason I can think of is for a Pork & Ride. There's no residential development there. If that particular location becomes more important then build a station at that time, not now. As for Sunbury North: the only reason you'd go north of Raes Rd is to avoid land resumptions or tunnelling. Going north places it further away from residential development by the looks of the map. I'm not too flash when it comes to house prices but I'm pretty sure land resumption out there wouldn't be a huge cost like it is in say, Caulfield or Huntingdale. Although the local council wants to have a station north of Raes Rd, so it might be better... who knows.
- Fair point. The southern route still has issues with the need to create a fair few occupational crossings, which makes me a bit squeamish. Creative civil engineering would be required to minimise the number of level crossings, and that's not my forte.
- Your assumption is that the line is travelling at grade at Loemans Rd. If you rummage around the VicRoads website you'll find plans to realign Sunbury Rd for the 'Bulla Bypass', which this project would have to piggyback onto for preparatory civil works. This would result in a rail flyover regardless of what the gradient lines say (and they're imprecise on Google Maps).
- No, that curve doesn't need realigning and there's no need.
Flygon: Running along Tullamarine Fwy sounds great, until you realise that Airport Drive has been specifically built to carry rail along most of its median. Airport Dr is the cheapest possible access option to Melbourne Airport. Adding extra stops is silly, the point of the railway is that it doesn't have to stop anywhere but Footscray & Sunshine before getting to Melbourne Airport. It's already going the 'long way around', it doesn't need any help to make it slower than going via the Tullamarine Fwy.
As for a stop at Bulla: Why bother?