A look at the Vline timetable (starting this weekend) reveals some interesting facts.
There are 403 services on the Ballarat Line over the week. This is an average of 57 services per day across the entire week.
The Ballarat line has 40% more services more per week than the Bendigo Line.
Many of these Ballarat services, close to 80% or approximately 350 per week terminate or originate in the Ballarat area. (running between there and Melbourne)
Most other services on the line which are shorter services not going to Ballarat terminate or originate at Bacchus Marsh.
Why you would want to electrify to Melton only when Bacchus Marsh is the terminus for the commuter style services I am not sure. Electrification? Yes of course. This line in any other jurisdiction would have already been electrified.
Would I do Macchus Marsh. Absolutely. What about Ballarat? the extra distance could be justified and should be done. 9 car EMU Vlocities as already suggested would provide a much faster service. The line is rated to 160 km/h in some parts I believe. To obtain those speeds electrification would be a better and cheaper option.
Victoria has cheap power. It is not going away any time soon. The only question I have is AC or DC for Ballarat? AC would be a better standard and cheaper to deploy.
Victoria you need to start thinking about coming out of the 1800's.
I have not done an analysis on the Geelong Line as yet.