According to the PTV website, V/Line operates a service between Melbourne and Adelaide, via Bendigo. This is described by a V/Line timetable as the ‘Adelaide Daylink’. The journey is lengthy, but economical, particularly for those on concession fares or with large amounts of luggage.
There is, however, an unadvertised alternative V/Line route from Melbourne to Adelaide which is, in my opinion, significantly better!
Instead of travelling via Bendigo, take the train from Melbourne to Ararat, a coach to Horsham, and then meet the Daylink for the remainder of the journey to Adelaide.
Compared with the route via Bendigo, this cuts the journey time by over an hour (departing on weekdays at 8:16 am, rather than 7:13 am). Since the latest update to the timetable, effective 1 December 2019, the journey also includes a 1-hour layover in Horsham, just in time for lunch, where the options for food are substantially more varied (and cheaper!) than those scheduled on the Daylink.1
The journey can be booked directly through the V/Line plan trip/buy tickets page online, and selecting the correct route.
Because this route is cobbled together from various other routes, the timetables can be hard to interpret. For reference, I have compiled the relevant timetables into a combined ‘Melbourne to Adelaide via Ararat’ timetable, available here.
Prior to the new timetable, as at June 2019, the route instead involved a less-appealing 1-hour layover in Dimboola. ↩